208 



Stoliczka says " the obsoleteness of the ribs towards the umbilicus " 

 is "generally very 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 nancs."f 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 distribution of Jfaploceras planulatum is very exten- 

 sive. In the " Palaxmtologia 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 Switzerland, and " it maintains the same 

 geological horizon of the Middle Cretaceous " in Germany, Hungary 

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

 rocks of the Andes of Venezuela, in strata of the same age at Daghes- 

 tan, as well as from many localities in Southern India.! 



HAPLOCERAS CUMSHEWAENSE. (N. Sp.) 

 Plate 24, fig. 1. 



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

 pressed whorls, which increase somewhat rapidly in size : periphery 

 narrowly rounded : umbilical margin abruptly truncated at nearly a 

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

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

 ture semi-elliptical, nearly 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 ribs, which are dichotomous, bi-dichotomous, or trifur- 

 t-ating, but rarely simple, also by distant flexuous grooves or periodic 

 arrests of growth, which rnn 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 denned arrests of growth, and the ribs, 

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

 :ip:irl 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, 



Palaeontologia Indica, Fossil Ophalopoda of Southern India, p. 135. 



t Pal(5ontologic 8uisse, Fossiles de Ste. Croix. Vol. I, p. 284. 



J Palaeontologia Indica, Fossil Cephalopoda of Southern India, pp, 136-137. 



