172 L. Jf. Lanibe — Fish Fauna of the Albert Shales. 



Canobius modulus (Dawson). 



Palieoniscus (Rhadinichthys) modulus Dawson 1877. Canadian 

 Naturalist, new series, vol. viii, p. 338, "figs, a-d; and 1878, 

 Acadian Geology, 3d edition, supplement, p. 98, figs, \8a-d. 



This fish is short and robust, the mandibular suspensorium 

 is apparently nearly vertical, the head is blunt in front, and 

 enlarged ridge scales, in a row, pass backward from the occiput 

 to the dorsal fin and occur again in advance of the caudal fin. 

 These characters suggest its being referable to Traquair's 

 genus Canobius rather than to Rhadinichthys, to which genus 

 it was assigned when first described. 



It reaches a length of 59 mm with a depth in advance of the 

 dorsal fin of 15 mm . The length of the head, including the oper- 

 cular apparatus, is a little less than one-fourth of the total 

 length. The snout is rounded and projects beyond the lower 

 jaw. The orbit is large and placed far forward. The bones 

 of the head are ornamented with well-defined, short vermicu- 

 lar ridges, and tubercles, the former being generally in the 

 direction of the bone. The mandibular suspensorinm is nearly 

 vertical and thus differs from that oi Rhadinichthys , which is 

 oblique. The dorsal and ventral fins are triangular and of fair 

 size, the former slightly larger than the latter. The dermal 

 rays are delicate and seem to bifurcate distally ; they are articu- 

 lated, with the exception of the principal ones of the pectoral 

 fins, which apparently are not articulated, at least proximally. 

 Fulcra occur on all the fins. The anal fin is opposite the 

 dorsal, and the ventral pair is slightly closer to the anal than to 



EXPLANATION OF FIGUKES. 



Figure 1. Rhadinichthys alberti, anterior flank scales from a specimen 



from the Albert mines, in the collection of the Geological 



Survey ; eight times the natural size. 

 Figure 2. Rhadinichthys alberti, anterior flank scales from the type of 



R. cairnsi ; similarly enlarged. 

 Figure 3. Elonichthys broivni, flank scales, from two rows next above the 



lateral line, midway between the head and the dorsal fin, in 



the type specimen ; six times the natural size. 

 Figure 4. Elonichthys broivni, flank scales next above those of the lateral 



line, beneath the front end of the dorsal fin in the type 



specimen ; six times the natural size. 

 Figure 5. Elonichthys ellsi, anterior flank scales from the type specimen ; 



enlarged eight times. 

 Figure 6. Elonichthys ellsi, posterior flank scales, from a little above tbe 



mid-height of the body in line with the back part of the 



dorsal fin ; similarly enlarged. 

 Figure 7. Canobius modulus, anterior flank scales, from the two rows 



beneath the lateral line scales, in the type specimen from 



Beliveau, N. B.; twelve times the natural size. 

 Figure 8. Canobius modulus, posterior flank scales, beneath those of the 



lateral line, in the type specimen ; similarly enlarged. 



