114 'lightning' AND 'porcupine' MOLLUSCA. [Mar. 6, 



typified by T. gemmulatus of Philippi'. The peculiar apex may be 

 compared to the stiliform process of lanthina and Stilifer : and 

 there are several other genera, such as Ceecum and Turritella, in 

 which the embryonic spire, which had become useless for the occu- 

 pancy of the moUusk, is decollated or plugged up. The present 

 genus is allied to Fossarus. 



/ Iphitus tuberatus", Jeffreys. (Plate XX. fig. 12.) 



Shell forming a short cone, solid, opaque, of a dull hue : sculp- 

 ture, spiral ridges covered with numerous minute tubercles or beads ; 

 there are four or five of these ridges on the last whorl, three on the 

 penultimate, and two on the preceding whorl ; the base is also en- 

 circled by fine spiral striae ; the stiliform process had been broken off, 

 but sufficient remains to show that it was closely striated lengthwise, 

 as in the fossil species which I have noticed : colour white with a 

 faint tinge of yellow : spire rather short : whorls 3, besides the 

 stiliform process ; the last or body-whorl is three or four times the 

 size of all the others put together ; the point of the stiHform or cy- 

 lindrical process in the fossil shell is slightly twisted and blunt : suture 

 deep : mouth rounded, angulated above : outer lip sharp, scalloped 

 by the spiral ridges, expanded and reflected at the base of the pillar ; 

 inner lip wanting or inconspicuous : umbilicus none : operculum yel- 

 lowish-brown, having four or five volutions, the innermost being very 

 small ; these are crossed by curved and numerous striae in the line 

 of growth, as in species of Littorina. L. 0075, B. 0"05. 



•Porcupine' Exp, 1870: Atl. St. 6. A single but living speci- 

 men. 



Summary of the foregoing List. 

 Families. Genera. No. of species. 



VI. SCISSURELLID^ .... Scissurella 3 



VII. TROCHID^ MoLLERiA 2 



Cyclostrema 13 



Tharsis 1 



Ganesa 2 



CiRCULUS 1 



Trochus 32 



Olivia 1 



VIII. TURBINID^ Turbo 2 



Phasianella 1 



IX. LITTORINID^ Lacuna 3 



CiTHNA 5 



Littorina 3 



Iphitus 1 



Total 70 



' 'The same name {Gemmida) was also proposed by Weinkauff to clistinguish 

 a group or section of the genus Pkitrotoma. 

 " Covered with tubercles. 



