REPORT ON THE GASTEROPODA 583 



Philippi's generic diagnosis of Fossarus (Archiv. f. Naturgesch., 1841, vol. i. p. 42) gives an edentulate 

 inner lip as a characteristic feature, yet in Fossarus ambiguus (Linne), which is the original type of 

 the genus, there is a blunt tooth and a slight sinus or groove on the front of the pillar. As to the 

 large umbilicus which is constantly attributed to Fossarus ambiguus, it is often a mere chink, and 

 occasionally is quite absent. Of an epidermis, I confess I have never seen a trace. 



5. Iphitus, Jeffreys, 1883. 



Iphitus tuberculatus, n. sp. (PI. XLVI. fig. 5). 



Station 24. March 25, 1873. Lat. 18° 38' 30" N., long. 65° 5' 30" W. Off Culebra 

 Island, West Indies. 390 fathoms. Pteropod ooze. 



Shell. — Triangular, carinated, conical, strong, tubercled, glossy : with a stiliform but 

 slightly tumid tip, a short flat-sided spire, a linear suture, a flat short conical base, a 

 strongly varixed lip, and a small circular marginated mouth. Sculpture : there are on each 

 whorl two broad and strongly tubercled spiral threads ; on the body-whorl there are two 

 more of these, one just at or below the periphery, the other near the middle, and con- 

 tinuous with the strong labral varix ; on the stiliform process these are absent. Colour 

 glossy white. Spire conical, with a very slight convexity. Apex : the stiliform process 

 consists of three cylindrical whorls, of which the second is a little tumid ; the first two 

 are smooth, the third is scored with about six rounded spiral threads. Whorls 7^ to 8 in 

 all, of very slow increase, the last is strongly angulated round the base. Suture slightly 

 impressed, scarcely oblique. Mouth very small, very obliquely cut off from above down- 

 wards and backwards, round as in Scalaria, with a strong, prominent, continuous margin 

 all round. Outer lip a little descending, enormously thick, having a strong varix and a 

 double interior margin. Inner lip prominent on the body, where there is a sharp deep 

 little cleft between the lip and the body-whorl ; on the very short pillar the second margin 

 of the mouth becomes prominent, and rises into a cord, with a minute furrow between it 

 and the second basal spiral, which is continuous with the varix. H. 0'07 in. B. 0'049. 

 Mouth, externally 0"027 each way, internally 0-017 each way. 



This is an interesting addition, and of a more fully grown specimen to Dr Gwyn Jeffreys' curious 

 little genus (see Proc. Zool. Soc. Lond., 1883, p. 113, Iphitus tuberatus, p. 114, pi. xx. fig. 12). The 

 form of the mouth in his specimen was suggestive of a young shell, and this view the Challenger 

 species seems to confirm. The absence of longitudinal stria} on the stiliform process indicates that 

 this feature is specific, not generic. 



