1884.] 'lightning' and 'porcupine' EXPEDITIONS. 345 



species which might else be treated as mere varieties of other species. 

 I shall be pleased if my 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 with- 

 out regard to preconceived notions. In corroboration of my 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 Odo- 

 stomia of Fleming as a synonym of Rissoa ! 



A. Typical. Smooth or variously sculptured, and always dentated. 

 i 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 fins. 



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, Loven. 



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 ; 6-163g 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. 



i/ 3. Odostomia suboblonga 1 , Jeffreys. (Plate XXVI. fig. 3.) 



Shell conic-oblong, of moderate thickness, semitransparent, and 

 glossy : sculpture none except a slight keel which encircles the 

 periphery in young aud 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. 



6 



