258 ROYAL SOCIETY OF CANADA 
growth of the shell: they are three in number, and perhaps are only the 
outer laterals, for on the inner band (transmedians ?) no-scars have been 
detected. 
The central muscles (anterior adductors, etc.) rest on a quadrangular 
shield, considerably in advance of the laterals: each set is included in a 
somewhat pear-shaped area, which has an elliptical scar in front, and a 
deep, narrow scar on the inner side. The front of the visceral cavity 
probably is indicated by an isolated scar half way between the central scars 
and the anterior margin. The vascular trunks on this valve have not 
been observed. 
The dorsal valve is obovate and has broad, flat, lateral margins, that 
were partly external to the edges of the ventral valve.! A visceral callus 
of the shell at a young stage shows lobed divisions, produced by the 
advance of the central and lateral muscles as in Lingulepis pinneformis : 
outside of these we see the lines of progression of the same muscles over 
a shell surface from which the visceral callus has been exfoliated ; on this 
surface are exhibited the imprints of the central (anterior adductor) 
and interior lateral (transmedian ?) muscles: the position of the anterior 
adjustors is indicated at the point of the impression of the visceral callus 
in front of the centrals. The vascular trunks sweep forward from the 
sides of the shell, with a slight curve toward the front, and are separated 
by a space marked with vascular lines ; no branches were observed. 
The anterior parts of both valves are abundantly marked by the 
fimbriated edges of the mantle margin. 
Sculpture—Externally the valves of this species appear to be smooth, 
except for the numerous concentric raised lines of growth ; these are 
particularly numerous on the convex posterior portion of the ventral 
valve. A lens of half-inch focus exhibits a minutely cancellated surface 
on the lateral slopes of the valves. 
Size.—Length of ventral valve, 18 mm.; width, 14mm. The dorsal 
is 2 or 24 mm. shorter. 
Horizon and Locality.—Pale brown sandstone from Beverly, Ont. 
This species exhibits affinities to Lingula rather than Lingulella ; as 
witness the absence of an area on the ventral valve, and the transverse 
position of the anterior adductor muscles of the dorsal valve. Among 
species whose interiors have been figured, that of Lingulepis pinnæformis, 
Hall, closely resembles that of the Beverly form. 
The course of the vascular trunks and the attitude of the muscu- 
lar scars of the central group easily distinguish this genus from Lingu- 
lella. 
1 The features of this valve are described from several different specimens, no 
sinzle valve having been found in which all were visible. 
