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Show 1884.] ' L I G H T N I N G ' A N D ' P O R C U P I N E ' E X P E D I T I O N S . 345 species which might else be treated as mere varieties of other species. I shall be pleased if m y brother conchologists will take the trouble to read the observations which I have to make in the course of the following pages, and will consider the question impartially and without regard to preconceived notions. In corroboration of m y opinion that the presence or absence of a " tooth " or columellar fold does not of itself constitute a generic character, I would refer to some judicious remarks by Dr. Fischer in the * Journal de Conchyliologie ' for 1865. I may take this opportunity of noticing, par parenthese, that Philippi, in his generally useful 'Handbuch' (1853), gave Odostomia of Fleming as a synonym of Rissoa ! A. Typical. Smooth or variously sculptured, and always dentated. 1. ODOSTOMIA ELECTA, Jeffreys. O. electa, Proc. Zool. Soc. 1883, p. 394, pi. xliv. f. 3. 'Porcupine' Exp. 1869 : St. 4. A single but perfect specimen. Distribution. Between the Hebrides and Faroes (' Triton ' cruise) ; 516 fms. Allied to Liostomia eburnea of G. O. Sars; but, besides being very much smaller, the apex of the spire in the present species is abruptly and obliquely truncated, and the suture is not excavated as in the other species. 2. ODOSTOMIA CLAVULA, Love'n. Turbonilla clavula, Lov. Ind. Moll. Scand. p. 18. O. clavula. B. C. iv. p. 118 ; v. p. 211, pi. lxxiii. f. 1. 'Porcupine' Exp. 1869: St. 2, 18. 1870: Atl. Vigo B, 13. Distribution. Lofoten I. to Smyrna ; 6-163| fms. Fossil. Pliocene : Calabria and Sicily. A variety appears to be O. pistillus, afterwards pistilliformis of Brugnone. This species is always distinguishable by having the shape of a short cylinder with a truncated apex. 3. ODOSTOMIA SUBOBLONGA \ Jeffreys. (Plate XXVI. fig. 3.) S H E L L conic-oblong, of moderate thickness, semitransparent, and glossy : sculpture none except a slight keel which encircles the periphery in young and half-grown specimens, and gives them a somewhat angular appearance : colour ivory-white : spire shortish ; nucleus not prominent, and twisted inwards : whorls 4-5, slightly compressed but not flattened, gradually enlarging; the last equals two thirds of the spire when the shell is placed with the mouth upwards : suture shallow : mouth pear-shaped, somewhat contracted above and expanded below; its length is between one half and two fifths of the spire; inside smooth : outer lip rather thick-edged : inner 1 Somewhat oblong. |
