278 
BULLETIN OF THE NATURAL HISTORY SOCIETY. 
The precedino" summary g'ives a “bird’s-eye view’^ of the rela- 
tion in mimliers of the several classes and orders of Cambrian 
animals and plants found in the eastern provinces of Canada, 
and serves to emphasize the prevalence of certain types and 
the absence of all the higher orders as well as some of the 
lower ones that are common at the present day. No verte- 
brates and none of the higher Crustacea appear. True corals 
and the Bryozoa are absent. 
The Echinoderms are represented by a few Cystids. The ex- 
treme weakness in number of the Lamellibranchs or Pelycepods 
is notable, for though regarded as one of the lower classes of 
Molluscs, they do not show as much strength as some of the 
higher. 
The removal of Ilyolithidm (which are to be regarded as Ben- 
thos rather than Plankton), greatly weakens the Pteropoda ; there 
remains in this division only two genera of small species of pel- 
agic habit which are thought to have relations with this group 
rather than with the worms. 
The Gasteropoda show a number of varied and ancient types,, 
but the Cephalo])oda would not appear in this list if there were 
not an Ordovician fauna in the uppermost part of the St. John 
terrane which otherwise is Cambrian. 
The large number of species included in the Annelida is due to 
the fact that we have included here the Hyolithidm which by the 
great Barrande and many subsecjnent writers were included in the 
Pteropoda. The arguments for this have been shown in some of 
the papers referred to in this catalogue and need not be repeated 
here. It will jirobably be found that Orthotheca should be includ- 
ed in Volborthella; the writer cannot distinguish the latter from 
a small decollated Orthotheca. A study of the cpiestion bv some 
Russian author with larger material in hand is desirable. 
It will easily be seen that Brachiopoda and Trilobita are the 
dominating types of Cambrian animals. 
