66 



The Canadian Field-Naturalist. 



Vol. XXXV. 



more highly developed brain may have put 

 the huge stupid dinosaurs to a disadvant- 

 age in the contest for subsistence. In the 

 most recent formation from which dino- 

 saurian remains have been collected, (the 

 Lance formation) there are only a few 

 genera represented, which seems to point 

 to the gradual rather than sudden exter- 

 mination of the order. Certain families of 

 turtles, crocodiles and fishes which existed 

 with the later dinosaurs have persisted to 

 the present day with very little change. 

 That the dinosaurs evolved very rapidly 



is shoAvn by the fact that with few excep- 

 tions a geiius did not persist from one 

 geological subdivision to another. For 

 example in the Edmonton formation, which 

 is separated from the Belly River forma- 

 tion by about six hundred feet of marine 

 shales, we do not find the same genera that 

 are found in the Belly River formation, 

 though in several cases the line of descent 

 is quite apparent. Geologically speaking 

 these formations are quite close together 

 in time. 



A CYPRINID NEW TO SCIENCE. 



By Philip Cox, Ph.D., University of 

 New Brunswick. 



This minnow (Leuciscus ruhrilateralis 

 Cox) was discovered by the writer in the 

 summer of 1897 while he was investigating 

 the fresh-water fishes of the peninsula of 

 Gaspe, P.Q. It was generally associated 

 with Conesius plumbeus Agassiz, but in 

 some of the rivers, i.e. Nouvelle and Grand 

 Pabos, it was the dominant form. At that 

 time the fish was diagnosed as the eastern 

 representative of C. dissimilis Girard, or a 

 variety of C. plumbeus ; and, as the latter, 

 was reported to the Royal Society of Can- 

 ada (Fresh Water Fishes and Batrachia 

 of the Peninsula of Gaspe and their Dis- 

 tribution in the Maritime Provinces of 

 Canada, by Philip Cox, Ph.D., Trans. 

 Royal 8oc. Can., Vol. V, Sect. IV, p. 148, 

 1899). 



A subsequent and more critical study of 

 the few specimens preserved seemed to 

 confirm that view, and it was published as 

 C. p. rubrilateralis Cox (Cyprinidae of 

 Eastern Canada, Bull. No. II., Proc. Nat. 

 Hist. Ass., Miramichi, 1901, p. 42). 



In August, 1918, numerous specimens of 

 this minnow were taken by the writer in 

 Black Brook, Loggieville, Miramichi, N. B., 

 and carefully diagnosed, when the two 

 most important characters, namely, the 

 u5intal formula and the presence or ab- 

 sence of the barbel were more satisfactorily 



determined from the examination of a 

 large quantity of fresh material. It was 

 then seen that its affinities were with the 

 genus Leuciscus rather than with Conesius, 

 and that it was entitled to full specific 

 rank. 



The Gaspe fish are small, rarely exceed- 

 ing four inches in length, but, like all the 

 cyprinids of the peninsula, are brillantly 

 colored, the males well deserving the name 

 ''redfish", by which this species is known 

 locally in Loggieville. The Miramichi 

 Redfish are much larger, often attaining 

 a length of six inches, but the coloration 

 is dull, except in the breeding season, when 

 the rosy hues are intense on the males but 

 only perceptible on the females. 



The accompanying plate shows an exam- 

 ple of C. plumbeus above, and two Black 

 Brook specimens of L. rubrilateralis, a 

 female, and a male, below. 



The type may be described as follows : 

 Body robust, cylindrical, head and cau- 

 dal peduncle slightly compressed; dorsal 

 curvature less than ventral. 



Head 41/2-4% ; depth 5 ; snout 4-1/3 in 

 head ; eye small, 5 in head, 1-1/3 in snout ; 

 D. 8, A. 8 ; scales 12-72-8 or 9. 



Head short, rounded above ; snout, blunt- 

 ish; mouth small, oblique, lower jaw in- 

 cluded ; maxillary not reaching the orbit ; 



