218 F. B. Meek on the Family Pteriide. 
This genus includes @. grypheatus and G., tenuistriatus (= Avie 
ula grypheata and A. tenuistriata, of Munster, Gold; Petref. Germ, 
ii, 127-8). 
“In the same group may also be placed, as the type of a dis- 
tinct subgenus, another little Triassic species described by Mun- 
ster as Avicula decussata (Goldf. Petref. Germ. ii, 128, cxvi, 12a, b), 
For this form I would propose the subgeneric name Actinophorus, 
It agrees with the typical species in all essential characters, ex: 
cepting in being much more oblique, in having its posterior 
margin truncated at right angles to the hinge, instead of being — 
slightly sinuous; and particularly in having the left valve orna 
mented with strongly elevated, distant, radiating coste or plr 
cations, 
I have not been able to see the prismatic structure in either of 
these types, but, from all analogy, I should suppose it could be 
detected in specimens in a better state of preservation. So far 
as known to the writer, this genus has not been discovered im 
a and has only been found in the St. Cassian deposits of 
e Tyrol 
yrol, | 
Under the Aviculine or Pteriine, it will also be observed that 
. . 1s 
Schlotheim, = Monotis speluncaria of King and others); as 
E. radialis (= Peeten radialis Phillips); and &. Garforthensis, 
(=Monotis Garjorthensis King). This genus may be described 
as follows :— 
convex, the left valve being usuall very convex, and the right 
flat or a little concave; not distinctly auriculate, the ears being 
cle large and subcentral, those of the retractors small and sa | 
near the beaks. Surface generally with radiating, vaulted, ait 
~The species of this genus have been usually referred t Bunt. a 
eo a eee 
