786 REPORT—1896. 
Three local faunas, all older than Paradoxides, have been made known since 
Bergeron’s paper was written. They all show more or less the increasing 
prevalence of larval features in the trilobites as we go back in time. J. C. Moberg 
has described a number of species from Sweden, including two species of Olenellus, 
in which some of the above larval characters are shown. 
J. F. Pompeckj has just described a pre-Paradoxides fauna from Bohemia in 
which are a few trilobites that possess larval characters. Thus his Ptychoparia is 
referred to sub-genus Conocephalites, probably because it has a long eyelobe.! It 
is a primitive form with short pleure, if we may judge from the short posterior 
extension of the dorsal suture. His Solenopleura also differs from that genus in 
its long eyelobe and long glabella, but these also are larval features. Another 
species of Solenopleura, however, cited by Pompeckj, has shorter eyelobes. 
It is the Protolenus fauna of the St. John group (Cambrian), however, which 
shows most decidedly larval traits in its adult trilobites. 
Among these trilobites all (so far as their remains show it) have prolonged 
eyelobes, a peculiarity which marks the early Olenide. Many of them have long 
cylindrical glabellas, also a larval character. Many have a short posterior extension 
of the dorsal suture, indicating the primitive feature of short pleure. Many have 
small and weak pygidia ; this is inferred from the rarity of this part of the organism 
in the collections preserved. 
Protolenus (typical), which has a general resemblance to Paradoxides, differs 
from it in the absence of a clavate glabella, and the small anterior lobe of this part 
of the head-shield; but these are characters found in the larval stages of 
Paradoxides. 
A genus of this fauna, although not as common as Protolenus, is Ellipsocephalus : 
this genus also abounds with Protaspian peculiarities. 
Lastly, one may refer to the genus Micmacca, which has the following larval 
features, long cylindrical glabella, long eyelobes, short posterior extension of the 
dorsal suture. If Zacanthoides, of the middle Cambrian, were shorn of its long 
posterior extension of this suture and its long pleure, it would not differ greatly 
trom Micmacca. 
In the Olenellus fauna, also, are genera such as Olenellus, Protypus, Avalonia, 
and Olenelloides, which retain marked larval characters. 
Brachiopoda, 
If we turn our attention to the Brachiopoda, we note that they show a special 
development in the early Cambrian, different from that of the Paradoxides beds, 
and the later members of the Cambrian system. 
The most notable feature is the large percentage of Obolide (including 
Siphonotretine). The older Cambrian holds in common with the Paradoxides 
beds, the small shells of Acrothele, Acrotreta, and Linnarssonia; but it also has a 
series of larger forms peculiar to it: such are Obolus, Botsfordia, 'rematobolus and 
Siphonotreta of the Protolenus fauna, and Schizambon and Michwitzia of the 
Olenellus fauna. This great development of oboloid shells is not repeated until 
Ordovician time, 
Not only are these old Cambrian faunas remarkable for the peculiar types of 
Brachiopods which they possess, but they are also notable for those they lack. A 
true Lingula has not been found, though Lingulella is a common genus. 
The larval growths of Ordovician and Silurian Lingule carry us back to a form 
which is Oboloid. Thus in Z. guadrata, L. Howleyi, &e., the cell is first circular 
as in Obolus, then oval as in LZ. Quebecensis, &c., and finally takes on the sub- 
quadrate form of the adult shell. But there is a more elementary form of the 
Brachiopod shell than the circular shell of Obolus: this is seen in Paterina and the 
young shell of Botsfordia, which is nearly semicircular. Both these shells come 
from beds that are older than Paradoxides, 
\ Tn the larval forms of P'tychoparia and Solenopleura of the Paradoxides beds, 
however, the eyelobe is short. 
