208 



Stoliczka says " the obsoleteness of the i-ihs towards the umbilicus " 

 is " generally v-eiy constant in this species,"* and Pictet describes the 

 ribs as becoming narrow on the inner half of the sides and as disap- 

 pearing "vers la moiti^ des flancs."t In the smallest specimen from 

 Cumshewa Inlet, the original of figure 1 on Plate 28, the ribs are as 

 strongly marked on the umbilical margin as they are. on the peri- 

 phery, though this remark will not apply to the two large specimens 

 from the same locality. 



The geographical diHU-ilmiiou ot' If(( placer as planulatum is very exten- 

 sive. In the " Pala^ontologia Indica " it is stated to occur in the 

 Chalk Marl and Upper Greensand of England, in the Gault and " Gres 

 Verts" of Prance, Savoy and 8witzerhui<l, and "it maintains the same 

 geological horizon of the JMiddlc Cretaceous " in Gei-nuiny, Hungary 

 and the Carpathians. It has also been recognized in the Cretaceous 

 rocks t)f the Andes of Venezuela, iu strata of the same age at Daghes- 

 tan, as well as from many localities in Southern India.;}; 



Haploceras Cumshewaknse. (N. Sp.) 

 Plate 24, lig. 1. 



Shell composed of few (probably of three or four) strongly com- 

 pressed whorls, which increase somewhat rapidl}'^ in size : periphery 

 narrowly rounded : umbilical margin abi-uptly truncated at nearly a 

 right angle to the sides : umbilicus about one-tburth the entire 

 diameter and exposing one-half of the sides of the inner whorls. Aper- 

 ture semi-elliptical, neai-lj' twice as high as broad, squarely truncated 

 at the base and deeply emarginated by the preceding volution. 



Surface of the outer whorl marked in the cast by obliquely trans- 

 verse, flexuous I'ibs, which are dichotomous, bi-dichotomous, or trifur- 

 cating, but rarely simj)le, also by distant flexuous grooves or periodic 

 arrests of growth, which run parallel to the ribs and which can 

 scarcely be distinguished from the furrows which alternate with each 

 rib except by their being a little broader and deeper. On the last 

 whorl of the only specimen collected there would appear to have been 

 about twelve of these obscurely defined arrests of growth, and the ribs, 

 which are acute and somewhat crowded, are not quite two millimetres 

 apart on the periphery near the aperture. 



North shore of Cumshewa Inlet : a single fragment. 



This shell may be only a variety of the Ammonites Brewerii of Gabb, 



* Palasontologiii Indiua, Fossil Cephalopoda of Southern India, p. 135. 



t Paldontologie Suisse, Fossiles de Ste. Croix, Vol. I, p. 284. 



X Palaeontologia Indica, Fossil Cephalopoda of Southern India, pp, ]3G-1.'57. 



