Geological Society. 345 



Since that date two very fine specimens have been obtained, both 

 from Calne — one by Mr. Keeping, sen., now in the Woodwardian 

 Museum, Cambridge, the other in Dr. Wright's collection. These 

 show the affinities of the Echinid to be rather with the Echinothu- 

 ridae. The author regards this species as the type of a new genus, 

 which he names Pelanechinus, and characterizes as follows : — 



Test thin, circular, depressed, consisting of (1) transversely elon- 

 gated coronal plates, (2) apical plates, (3) an actinal system of im- 

 bricating plates around the mouth. Interambulacral areas narrow at 

 poles, but rapidly broadening towards the equator, with 6-8 rows of 

 primary tubercles ; the plates narrow, contour rounded, slightly un- 

 dulating. Ambulacral areas more uniform, equal to ^ of the greatest 

 breadth of interambulacral areas, with two rows of primary tuber- 

 cles ; poriferous zones broad ; pores trigeminal in the equatorial re- 

 gion. Primary tubercles rather small, smooth, perforated, uniform 

 over both areas ; spines small, hollow. Peristome deeply notched. 

 Actinal area about g of whole test, covered with zones of large im- 

 bricating plates, with perforations and perforated tubercles. Jaws 

 large and powerful. 



This Echinid has a marked similarity of appearance to Astheao- 

 soma (Calveria) ; and the author believes that it also had a flexible 

 test. 



2. " Eemarks on Saurocephalus, and on the Species which have 

 been referred to that Genus." By E. Tulley Newton, Esq., E.G.S., 

 of H.M. Geological Survey. 



In this paper the author gives an account of those species of fossil 

 fishes from American and British Cretaceous strata which have been 

 referred to the genus Saurocephalus, originally founded by Harlan 

 in 1830, and regarded by him as showing lleptilian affinities. The 

 ichthyic nature of the species first described, S. lanciformis, Harl., 

 was demonstrated by Prof. Owen. By Agassiz and Dixon certain 

 large fossil teeth from the White Chalk of Lewes were identified 

 with Sauroa'2)halus lanciformis ; and the latter also figured an elon- 

 gated rostrum as belonging to this fish. Dr. Leidy, in 1856, rede- 

 scribed the original specimen of Saiirocephalus lanciformis, and 

 maintained that the jaws and teeth figured by Dixon do not belong 

 to the genus Saurocej^haJus ; he proposed for them the new name of 

 Protosphyrcena ferox. He thought also that the rostrum figured by 

 Dixon belonged to a Sword-fish, and named the species Xiphias 

 Dlxoni. Specimens since obtained by Prof. Cope in America have 

 proved that the rostrum and teeth actually belonged to the same 

 fish, for the reception of which and of some American species Prof. 

 Cope established the genus ErisichtJie. The author maintains that 

 Dr. Leidy's name, Protosphyrcena, must be adopted for this genus, 

 which will include the British Protosphyrcena ferooc (==Erisichthe 

 Dixoni, Cope) and the American species, P. angidata, niticla, pene- 

 trans, and zipjhioidts (Cope). The characters of these species are 

 discussed by the author. The species known on the Continent as 



