BY W. L. MAY. 65 



smooth keel on the base, which is otherwise plain. Aper- 

 ture subquadrate? (rather broken), with a short anterior 

 canal. Outer lip dentated by the sculpture. 

 Length, 7; breadth, l.G mill. 



Type, from 100 fathoms seven milts East of Cape 

 Pillar. Several others, mostly juvenile, from about 40 

 fathoms off Thouin Bay. This species is rather nearly 

 related to ('. trixcu/pto, May, which was described from a 

 half-grown shell. It is narrower, with weaker sculpture 

 and a different, though somewhat related proto-conch, 

 which seems to separate it from all other species. 



PI. XVI., figs. 21, 21a. 



Cerithiopsis mamilla, sp. nov. 



Shell small, pale brown, pyramidal. Whorls nine and 

 a half, rounded, including a .«imooth, bulbous proto-conch 

 of about two whorls. Adult sculpture consists of three 

 main keels, which are more or less nodulous, the central 

 one being rather the largest. They are separated by 

 equal sized, smooth spaces. There is a small smooth 

 keel below the others, which shows verv distinctlv on the 

 base, which is smooth. Aperture subquadrate, inner lip 

 very concave, outer lip dentated by the keels. There is 

 H short anterior canal. The keels on the upper whorls 

 are almost or quite smooth. As growth proceeds they 

 become faintlv, irregularly nodulous. On the three last 

 whorls the nodules are more distinct. 



Length, 5; breadth, 1.4 mill. 



Type, with ten others, from about 40 fathoms off 

 Thouin Bay, East Coast. 



Whilst the shape of the shell is fairly constant, and 

 the pullus alwavs the same, co-types show considerable 

 variation in the sculpture; whilst most are similar to the 

 type, they may be almost destitute of nodules, or there 

 may be three strongly nodulous keels on all the adult 

 whorls. 



PI. XVI., fig. 22. 



Orbitestella iredalei, sp. nov. 

 Shell minute, discoidal, smooth, white, spire flat. 

 Whorls about three and a half, square in section, 

 bicarinate, the upper carina at the angle being the largest, 

 and forming a spiral keel on the flat summit to the apex. 

 The flattened part of the whorl between the angle and 

 the suture is roundly elevated; base margined bv the 

 lower keel, otherwise smooth except for lines of growth, 

 which are in evidence over the whole shell, broadly, per- 

 E 



