Aldrich collection, Distribution of Ctenobranchia (in part), Aspidobranchia, and Scaphopoda in the Alum Bluff group of Florida and Georgia Continued The localities within each State and formation are arranged in geographic order from north to south and from west to east] [pr, Prolific; a, abundant; c, common; p, present; r, rare. Species Mitrella pedana Gardner, n. sp.... tytha Gardner, n. sp...... megala Gardner, n. subsp. ischna Gardner, n. sp...... Murex (Murex) chipolanus Dall. Paziella (Dallimurex) lychnia Gardner, n. sp...... Pteropurpura dryas Gardner, n. sp... (Talityphis) alatus obesus Gabb.. tribaka Gardner, n. sp..... veatchi (Maury).. Eupleura pterina Gardner, n. sp....... Personella floridana Gardner, n. sp....... Morum (Oniscidia) chipolanum (Dall ms) Gardner, n. sp....... Ficus copapyratia Gardner, n. sp.... Cypraea (Cypraeorbis) heilprinii Dall. (Cypraeorbis) chilona Dall....... (Cypraeorbis) tapeina Gardner, n. sp.... Trivia chipolana Maury. vaughani Gardner, n. sp........ Erato (Hespererato) chipolana Maury.... Natica (Natica) alticallosa Dall. Natica (Naticarius) precursor Gardner, n. sp......... (Stigmaulax) guppiana toulana Gardner, n. subsp.. (Tectonatica) mino Gardner, n. sp. (Tectonatica) semen Gardner, n. sp.... (Tectonatica?) platabasis Gardner, n. sp.. Polinices judsoni (Maury). Polinices? demicryptus Gardner, n. sp.. Enspira rotunda Gardner, n. sp....... waltonense Gardner, n. sp.. caractica (Dall).. Strombus aldrichi Dall.. Orthaulax gabbi Dall.. fornicata (Linnaeus). aesop Dall... plana Say....... Crucibulum chipolanum Dall.. chipolanum dodoneum Gardner, n. subsp.. multilineatum (Conrad).. Capulus chipolanus Gardner, n. sp.... Cheilea dryas (Dall ms) Gardner, n. sp.. florius Gardner, n. sp... myttonis (Maury)... Strombiformis scotti (Maury).. ischna Gardner, n. sp.... Gegania acutissima (Dall).. dodona Gardner, n. sp...... Modulus compactus Dall.. biconicus Gardner, n. sp.... Caecum chipolanum Gardner, n. sp..... Lemintina granifera (Say)... Petaloconchus sculpturatus H. C. Lea.. quadriseriata (Sowerby), subsp. alvear Gardner.... Turritella subgrundifera Dall.. alcida Dall.. bicarinata Gardner, n. subsp. (Torcula) dalli Gardner, n. sp....... (Torcula?) sp........ (Torcula?) mixta Dall.. (Torcula?) jacula Gardner, n. sp...... (Torcula?) chipolana Dall... "Vitrinella" seminola Gardner, n. sp.. waltonia Gardner, n. sp...... excavata Gardner, n. sp.......... Aldrich collection, Johns Hopkins University 3856 2645 2615 3732 3742 3731 10658 5080 5184 51955079 10661 10662 5193 3733 2238 3748 9958 7261 7264 9960 9957 10603 14436 10608 5618 10612 9959 Distribution of Ctenobranchia (in part), Aspidobranchia, and Scaphopoda in the Alum Bluff group of Florida and Georgia---Continued [pr, Prolitie; a, abundant; e, common; p. present; r, rare. The localities within each State and formation are arranged in geographic order from north to south and from west to east] Florida Shoal River formation Species "Circulus" mitorraphes Gardner, n. sp....... anthera Gardner, n. sp.......... Cochliolepis arietina Gardner, n. sp. Syncera microgaza Gardner, n. sp. Rissoina (Mirarissoina) juncea Gardner, n. sp.... (Zebinella) chipolana Dall.. (Cibdezebina) browniana D'Orbigny. vittata Gardner, n. sp....... Rissoa phagon Gardner, n. sp.... litiopaopsis Gardner, n. sp.. Smaragdia grammica Gardner, n. sp.... chipolana (Dall). Tricolia affinis chipolana Gardner, n. subsp. probrevis Gardner, n. sp........ Astraea dalli (Maury)...... (Lithopoma) chipolana Dall.. nanum eonanum Gardner, n. sp.. phacoton Gardner, n. sp.... Solariorbis microforatis Dall.... Chlorostoma (Omphalius) exolutum (Conrad). (Omphalius) exolutum limatum Dall.. Calliostoma grammaticum Dall.. metrium Dall..... exile Dall...... : p SYSTEMATIC DESCRIPTIONS Phylum MOLLUSCA Class GASTROPODA Order CIENOBRANCHIA Suborder STENOGLOSSA Family PYRENIDAE Genus MITRELLA Risso 1826. Mitrella Risso, Histoire naturelle des principales productions de l'Europe méridionale, vol. 4, p. 247. Type by subsequent designation (Cox, Rept. Paleontology Zanzibar, Moll., p. 28, 1927): Mitrella flaminea Risso = Murex scriptus Linnaeus. Recent in the Mediterranean. Shell dense, rather small, fusiform. Spire elevated, the whorls evenly tapering. Protoconch small, smooth, blunt, paucispiral. Sculpture restricted to the feeble striae that gird the pillar and the anterior fasciole. Aperture rather narrow. Outer lip thickened a little, feebly emarginate posteriorly; denticulate within. Parietal wash moderately heavy. Pillar feebly rugose. Anterior canal not defined, the fasciole little or not at all expanded. Terminal notch U-shaped, oblique. The Recent representatives are widely distributed in the warm and shallow waters. Mitrella pedana Gardner, n. sp. Plate LII, figure 9 little in front of the siphonal notch. Inner margin of aperture smoothly and strongly concave. Parietal wash thin. Pillar wash heavier, commonly rugose. Inner margin of pillar sharply keeled, the keel developing within the aperture into a well-defined marginal fold. Anterior canal very short, broad. Terminal notch broad, shallow, obliquely directed. Dimensions of holotype: Height, 4.7 millimeters; length of aperture, 2.0 millimeters; maximum diameter, 2.0 millimeters. Holotype: U.S. Nat. Mus. No. 371840. The conch of M. pedana is fusiform, with no remarkable characters, but the protoconch includes fewer volutions and is more obtuse than that of any other of the allied Chipola forms. The initial turn of the protoconch, instead of being flattened and almost entirely immersed in the succeeding volution, as in most of the species of Columbellopsis, is inflated and immersed only at the tip. The thickening of the labrum of the adult conch is also more slight than in the allied section. The anterior portion of the body whorl in Mitrella pedana is so feebly constricted that a reference to the section Columbellopsis does not seem justified. In the relatively few whorls and broad conical spire the species recalls Mitrella lunata (Say), of the Recent East Coast, and Mitrella ocellata (Gmelin), of the Caribbean fauna. The species is abundant at the type locality. Section COLUMBELLOPSIS Bucquoy, Dautzenberg, and Dollfus 1882. Columbellopsis Bucquoy, Dautzenberg, and Dollfus, Mollusques marins du Roussillon, vol. 1, p. 77. =Atilia auctores not Atilia H. & A. Adams, Genera Recent Mollusca, vol. 1, p. 184, 1853. Type by subsequent designation (Pace, Mal. Soc. London, Proc., vol. 5, D. 42, 1902): Columbella suffusa Sowerby. Recent in the Pacific. Shell small, fusiform; the maximum diameter falling a little in front of the median horizontal. Aperture nearly half as long as the entire shell. Body smoothly rounded at the base. Spire tapering somewhat irregularly to an obtuse apex; postnuclear whorls trapezoidal, sharp-edged posteriorly. Whorls of conch 4, closely wound, separated by distinctly impressed linear sutures. Protoconch small, smooth, highly polished, twice coiled; initial turn inflated, immersed at the tip; succeeding volution becoming decreasingly convex toward its close. Dividing line between conch and protoconch indicated by a slight axial thickening at the close of the protoconch and by the change in the texture of the shell. Incremental striae microscopically fine, more or less flexuous. Spirals, 4 or 5, low, rounded, closely spaced on the base of the body and the pillar, merging gradually into an equal number of more sharply rounded but finer lirations, which crowd the anterior fasciole. Aperture of moderate width, acutely angulated behind. Outer lip almost vertical from the commissure to the base, feebly emarginate at the posterior siphonal fasciole; a broad and ill-defined | notch perceptible. Parietal wash thinly spread over axial thickening developed a little behind the thin, sharp margin; inner surface reinforced with about half a dozen elongated denticles that increase in prominence from the anterior to the posterior, which is placed a Type by original designation: Columbella minor Scacchi. Recent, Pleistocene, and Tertiary of the Mediterranean region. Shell small, slender, with moderately elevated spire and a body abruptly constricted into a short and wide canal. Nucleus small, smooth, blunt, paucispiral. Whorls of spire closely appressed, regularly increasing in height and diameter. Surface smooth except for the lirations girding the pillar. Aperture rather narrow, obtusely angulated posteriorly. Outer lip varicose, sharp-edged but denticulate within, the posterior a narrow area. Inner margin of pillar oblique, not plicate nor acutely compressed. Anterior siphonal fasciole little or not at all expanded, strongly lirate. Terminal notch narrow, obliquely directed. Atilia has been used by many workers for the shells here included under Columbellopsis. The Adamses selected no type but listed 7 species, arranged alphabetically. The first named species, C. conspersa Gaskoin, has been commonly accepted, though there has been apparently no designation. Cossmann in 1901 cited Mitrella minor Scacchi as the type of Atilia, but minor was not included in the original list of the Adams species. Pace in 1902 cited "C. suffusa, Sby., selected by Chenu, 1859." Chenu named the species only as an "example," not a type, so the designation must date from Pace's citation in 1902. In case the question of the validity of Pace's unwitting designation should be raised, Grant and Gale, in 1931, made a formal designation of Columbella suffusa Sowerby as the type of Atilia and placed Atilia in the synonymy of Anachis H. & A. Adams, 1853. The differences which separate Columbellopsis from Mitrella-the constriction of the base of the outer lip to form a defined canal and the stronger tendency toward a terminal varix are of no more than sectional value. In the large group of Alum Bluff Mitrella, indeed, the line drawn seems so arbitrary that even a section separation places an overemphasis on the dif ferences. Judging from the distribution charts of the Alum Bluff, the section Columbellopsis and the genus Strombina are in large measure mutually exclusive, for Columbellopsis is characteristic of the Chipola fauna and Strombina of the Shoal River. The contrast in the make-up of the Chipola and Shoal River faunas is peculiarly striking in the Pyrenidae. In the collections which have been reviewed the number of individuals of Strombina in the Shoal River greatly exceeds the number of Columbellopsis in the Chipola, and yet the number of species of Columbellopsis involved is three times as great as the number of species of Strombina. Apparently the Shoal River fauna was one well adapted to a rather unusual environment, while the conditions under which the Chipola species lived must have been more varied and less favorable to any single group. Two out of the twelve species recorded from the Chipola are known only from the lower bed at Alum Bluff, and like so many of the Alum Bluff species they are coarser and more rudely sculptured forms than their Chipola River analogues. I have been unable to construct a key for Mitrella and the section Columbellopsis that would simplify the difficulties of their determination. Mitrella juncea Gardner, n. sp. Plate LII, figure 17 Shell small, polished, slender, elongate-conic. Aperture decidedly less than half as high as the entire shell. Body rather sharply rounded at the periphery, constricted into the short neck. Sides of spire flat tened, evenly converging. Tip broken away in all available material. Conch including probably 5 volutions, although the apex is decorticated and the exact number doubtful. Posterior edge of whorls sharp; sutures distinct. Protoconch imperfectly preserved, of moderate dimensions and including 3 or 4 volutions. Sculpture restricted to 6 or 7 low, flattened lirae that gird the pillar and anterior fasciole. Aperture rather narrow, sinuous, acutely angulated posteriorly. Outer lip feebly emarginate at the posterior fasciole, broadly and smoothly arching in front of the siphonal notch, smoothly but sharply rounding into the base, little or not at all thickened externally, reinforced internally; two rather prominent denticles, the posterior the more elevated, developed in the type a little in front of the notch. Inner margin of the aperture abruptly constricted at the base of the body. Parietal wash thin except directly in front of the commissure, merging into the heavier feebly rugose pillar callus. Pillar short, the inner margin sharply keeled. Anterior canal short, recurved. Terminal notch broad, shallow, obliquely directed. Dimensions of holotype: Height, 6.0 millimeters; length of aperture, 2.5 millimeters; maximum diameter, 2.1 millimeters. Holotype: U.S. Nat. Mus. No. 371842. Type locality: No. 3742, Shell Bluff, Shoal River, Walton County, Fla. The outer lip is more strongly emarginate at the posterior fasciole than in Mitrella tytha, more flaring in front of the fasciole, and less evenly lirate within. M. stikta from the Chipola is a close analogue. The general outline and dimensions of the two species are similar, but in the Chipola form, the spirals on the base of the body and pillar are more numerous, more elevated, and more sharply defined than in Mitrella juncea, the emargination at the posterior siphon is more shallow, the labrum less expanded anteriorly, and the obscure marginal fold upon the pillar is delimited by a shallow groove. Mitrella nanna, also from the Chipola, is smaller than M. juncea and even more slender. Mitrella juncea is not at all common even at the single locality from which it has been collected. Occurrence: Shoal River formation, locality 3742P. Mitrella tytha Gardner, n. sp. Plate LII, figure 24 Shell small, highly polished, slender, elongate-conic. | Aperture less than half as long as the entire shell. Body obtusely angulated at the periphery, the posterior portion of the body and the spire evenly and gradually tapering to the subacute apex. Whorls of conch between 4 and 5, sharp-edged posteriorly, separated by feebly impressed sutures. Protoconch moderately large in |