502 
LITUITES MULTICOSTATUS, Whitfield ( Geol. Wisconsin, Pl. xx, Fig. 7). 
TROCHOLITES MULTICOSTATUS, Whiteaves (Geol. Canada, Pal. Foss., 
Hi Peeler vd Pigs je 8 Pl. vin, Figs. 223s 
This interesting species of the Niagara fauna is given here in 
order to show the young neanic stage which was preserved in relief 
attached to the centre of a mould of the older whorls, Figs. 22, 23, 
Pl. viii. The close connection of Discoceras and Trocholites is 
demonstrated by thisdrawing. In fact, if separated at this age, the 
young would have to be placed in that genus. Fig. 21 shows the 
cast of a perfect mould of another specimen of the same species 
which has reached the ephebic stage. 
Whether this had a dorsal furrow in the umbilical perforation 
could not be determined. The perforation is certainly very small. 
Whiteaves’ figure shows that the siphuncle is subdorsan in the 
-ephebic stage as it is in the neanic stage described above. 
Systrophoceras,* n. g. 
This genus includes the remarkable series of costated trochoceran 
and gyroceran forms described by Barrande in his Systeme Stlurien, 
which have the whorls either very slightly in contact, or not touch- 
ing at any stage, and are devoid of an impressed zone. 
Systrophoceras ( Troch.) arietinum, rapax and pingue, sp. Barrande, 
have a depressed subtrigonal or subkidney-shaped outline to the 
whorl with the siphuncle dorsad of the centre, and in many charac- 
ters are distinct from the others cited below under the name of 
Peismoceras. ‘These species may have been close-coiled in their 
younger stages. 
Trochoceras. 
Barrande described this genus in 1848, and in the same publi- 
cation later gave a list of the species { in which the characteristic 
form, Zyochoceras Davidsoni, was mentioned first, and this con- 
sequently is his type. Hall described the same genus under the 
same name, but without knowledge of Barrande’s work in the 
Paleontology of New York,§ but his types are both quite distinct, 
and do not belong to any genus yet described from Bohemia. 
* Sbotpogos, rolled up. 
+ Haidinger’s Berichte, iii, p. 266, 1847. 
t Ibid., iv, 1848. 
2 Vol. ii, 1852, p. 336. 
