434 Canadian Record of Science. 
Pteropoda until some better ground can be shown for removing 
them to another group in the animal kingdom — better than have 
been shown by Hackel, Neumayr and Jhering. 
Pelseneer has lately fully and profoundly discussed the Palzeozoic 
groups which have been referred to Pteropoda, as to their relation- 
ship to living Pteropods, and showed that nearly all the chief char- 
acters of Hyolithes and Conularia are entirely wanting in the 
Pteropods now existing. Pelseneer refers the Pteropods to Ophis- 
tobranchia among the Gasteropods, considering that they have 
sprung from the Bullicz and Actzonide. The remains of Pteropod 
are wanting in nearly the whole of Mesozoic time, which is hard to 
understand if they had already appeared in numerous forms in the 
Paleozoic. Pelseneer shows with reagon that it appears to be a fixed 
law of nature thata group of animals once extinct can never 
reappear.! 
The result of Pelseneer’s investigations agree fully with Neu-— 
mayr’s statement that Hyolithes and Conularia cannot belong to 
i any living group, and thus can stand in no generic relation to the 
Pteropoda. In opposition to Neumayr he shows that they proba- 
My bly belong to widely distinct groups, but does not attempt to define 
i their place in the scale of being.” 
Likewise Walcott has been uncertain of the place of Hyolithes 
and Conularia, &c., though he places them under the category of 
Pteropoda as being in a measure representative of recent Ptero- 
poda, they differ in other respects so much that it appears as 
though a division of the Gasteropoda equivalent to the Pteropoda 
might consistently be made to receive them.* 
The fossil which Linnarsson described as Hyolithes levigatus is 
by G. Holm removed from that genus, and the new genus Torellella 
instituted for it. The shell as in Conularia consists of calcium phos- 
af) phate, the form is round, firm, weakly arched, of nearly equal 
breadth ; a compressed tube with elliptical section, of which the 
edge of the orifice must have been straight. He refers this shell 
as well as Salterella and Tentaculites to the Annelida. 
Of the Family Hyolithidee, Holm says that it contains only the 
genus Hyolithus, and that other genera have certainly been re- 
| ferred here erroneously. Some show themselves to be less well 
eo 
Se 
Hy 1 Pelseneer, P., Report on Pteropoda collected by H. M. S. Challenger during 
H 873-76—Zoology Vol. 23, London, 1888. 
* The connection with modern Pteropoda may be through Styliola and Creseis, 
Me &c., which collectively range through the Lower and Upper Silurian and Devo- 
vy al nian. Some of these minute forms may yet be detected in the Mesozoic rocks. 
G.F.M. 
® Second contribution to the study of the Cambrian faunas of North America’ 
j Bullet. No. 30, U.S. Geol. Surv., p. 131. See also Trans. Roy. Soc. Can., Vol. iii, 
h pt. iv, p. 47, 1885. 
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