40 
and very convex, the ridges are tolerably well marked, wavy 
and with confluent margins ; there is no punctation. The teeth 
of the fourth row are small, rhomhoidal, and deeply punctate. 
The affinities of the species are with S. magnum and 
sahreticulatus^ both of which it strongly resembles in general 
appearance, hut it is more deeply pitted than either. 
A careful revision of the genus is needed, and would lead to 
a rearrangement, the extent of which it is impossible to predict. 
But it is very probable that the species at present distinguished 
will hs grouped round three types, S. niagnus^ S. tenuis^ and 
S. Rigcmxi (favosus )—the last named species having a smaller 
jaw than either of the others. 
I must, in conclusion, express my obligation to Mr. A. Smith 
Woodward, of the British (Natural History) Museum, through 
whose kindness I was able to get access to the specimens in our 
national collection. 
H. M. PLATNAHEE. 
