1895. | NEW YORK ACADEMY OF SCIENCES. 133 
HIPPONICHARION CAVATUM PI. vii., figs. 2 @ and b. 
Trans. Roy. Soc. Can., vol. xi., p. 99, pl. xvii., figs. 3 a@ and b. 
This species also appears to be confined to Assise 1. Hip- 
ponicharion in all its species looks like the head shield of 
Microdiscus, but it is never bilaterally symmetrical as the head 
shield of a trilobite would be. 
HIPPONICHARION MINUS Pl. vii., figs. 3 @ and b. 
Trans. Roy. Soc. Can., vol. xi., p. 99, pl. xvii., figs. 4 @ and b. 
Several specimens of this species were found in the upper 
part of Assise 3, at Hanford Brook. 
BEY RICHONA.* 
Trans. Roy. Soc. Can., vol. iii., p. 65 
The original description of this genus was as follows: 
“Valves nearly or quite as wide as long and wider in front 
(behind) than behind (in front); they have a rudely semi-circular 
flattened area, extending not more than half way from the hinge- 
line; the rest of the valve is convex, and most elevated near the 
middle; the flattened area has several depressions which are not 
very prominent (7. e., conspicuous). 
“There is no median ridge, properly so-called, on the valve of 
this genus, but there are two very small oblique ridges, close to 
the hinge line of which the anterior (posterior) may be taken to 
represent the median ridge; the posterior (anterior) ridglet be- 
comes confluent with the inner termination of the anterior ridge. 
“The protuberances on the surface of the valves are not so 
marked in this genus as in Hipponicharion and Beyrichia.” 
Further discovery shows that this description in one respect 
is incorrect, and the words in brackets should be used to correct 
it. The species first descr.bed were so much alike at the two 
ends that it was difficult to determine which was the anterior; the 
present view is that the wider end is the posterior end of the 
vaive, but it is associated with the unusual condition that this is 
the thin end; the widest space within the valves is at the anterior 
end, and here also are situated the highest tubercle and the 
deepest pit. This remark applies to all the species, but with 
more force to those about to be described than to the ones on 
which the original diagnosis was based. 
I incline to the belief that the two species which Mr. Walcott 
has described and referred to Aristozoe of Barrande are of this 
genus, and especially his A. rofundata. Both have that high, 
* Augmentative of Beyrichia. 
