32 
MUSEUM BULLETIN NO. 3, 
Anticosti, a smooth brachiopod to which he gave the name of 
Athyris lara. He called attention to the fact that some speci- 
mens have a faint indication of a mesial sinus in the ventral valve, 
but are generally without either fold or sinus. 
In 1882 Davidson stated that Mr. Glass had been able to 
expose the spirals of Athyris lara and that these “entirely resemble 
those of A try pa, the apex of each vertical cone being directed 
towards the middle of the bottom of the dorsal valve.” These 
shells were collected by Doctor G. J. Hinde near Jupiter river 
and it is now known that they were not correctly identified. 
Specimens of Athyris lara which were collected at the type 
locality and compared with the proterotypes show that it is a 
true meristellid and probably to be referred to the genus Whit - 
fieldia. This leaves the shells whose structure was worked out 
by Mr. Glass without a name. The writer has also developed 
the internal structure of several of the Jupiter River shells 
and there is no question but that their spirals are of the atrypoid 
type. Externally they have the expression of Nucleospira t 
but lack the hirsute exterior. For atrypoids having these 
characters the generic name of Lissatrypa is proposed. 
Diagnosis. Shell of medium size, lenticular, subovate or 
subpentagonal in outline, greatest width near the middle ; 
both valves of nearly the same convexity, a faint sinus in some 
specimens at the anterior margin of the ventral valve, a corre- 
sponding small fold in the dorsal, in some specimens the anterior 
margin slightly linguate; hinge short, gently curved; no area; 
beak and umbones small, surface smooth with concentric lamel- 
lae; shell structure fibrous and on exfoliation it has a silky sheen. 
Beak of ventral valve closely incurved and in contact with 
the dorsal valve; foramen triangular, extending to the hinge 
line, no covering observed; teeth relatively large, diverging at 
an angle of about 135 degrees, summits rounded and curved 
slightly toward the centre of the shell ; they rise from the lateral 
slopes of the interior and are unsupported by lamellae ; muscular 
impressions apparently very faint. 
Dorsal valve with a faint sinus at the umbo; hinge plate 
composed of two diverging processes meeting at the apex at 
about 60 degrees; each has two longitudinal grooves dividing 
