TROCHOCERAS. 89 



5. Trochoceeas reticulatum, Phillips, sp. PL IX, figs. 7, 7 a, 7 h. 



1841. Ctetoceeas eeticulatum, Phil. Pal. Foss., p. 117, pi. xlviii, fig. 224. 

 1888. — — miieridge. Foss. Brit., vol. i. Pal., p. 167. 



Description. — Shell much arched. Whorls very slightly convex on the ventral 

 face, bent round suddenly to the sides, which are flat and perpendicular to the back ; 

 ornamented with numerous, fine, regular, longitudinal threads, distant about 1 

 mm., and crossed and knotted by twice as numerous, similar, transverse threads, 

 rather bent back in the centre of the back. Sides ornamented by very frequent, 

 elongated, strong, undulating, transverse waves or rounded ridges, which are most 

 marked on the elbow and almost gradually vanish as they slope back across the 

 ventral region. 



Size. — The specimen is too imperfect for measurement. 



Locality. — Wolborough. A single specimen, which is Phillips's type, is in the 

 Museum of Practical Geology. 



Remarks. — This specimen is a mere fragment, and gives but little insight into 

 the character of the species. Its markings are, however, well preserved, and in 

 its flattened side and in the nature of the major ornamentation it appears to be 

 quite distinguishable from the adjacent species. Mr. Foord supports me in 

 regarding the frequency and elongate character of these markings as suSicient 

 reason for regarding it as in all likelihood distinct. Phillips's figure fairly 

 represents it, save that the lines on the back of the fossil are much more obscure 

 than he depicts them, and that the meshing of the enlarged surface is drawn very 

 much too square. 



Affinities. — The species which it most nearly approaches is Tr. obliquatuniy 

 Phillips, sp. 



6. Trochoceras, sp. PI. IX, figs. 8, 8 a. 



P1852. G-TEOCEEAS, sp., Sandherger. Verst. Rhein., p. 139, pi. xiii, figs. 3, 3 a. 



Remarks. — In Mr. Vicary's collection is a fragment of a Cephalopod which 

 appears to belong to a species allied to Tr. pulcherrimum. It consists of about 

 two chambers of an arching shell. The section is unsymmetrically sub-quadrate, 

 and the ventro-dorsal diameter is less than the lateral diameter. At the ventral 

 elbow are distant nodes slightly produced longitudinally, and about five-fourths 

 times as numerous as the chambers. The walls of the chambers are very concave. 

 The siphuncle is near the centre on the ventral side, but is situated a little unsym- 

 metrically. The chambers are broad. The external layer is entirely absent. 



