No. l8.] TRIASSIC FISHES OF CONNECTICUT. 6l 



well preserved, and hence imperfectly known. The nature of 

 the dentition has been sufficiently indicated in the foregoing 

 family and generic diagnoses. 



Concerning the use or abandonment of Egerton's generic 

 term "Ischypterus" we shall waste no time in killing dead lions. 

 In this, as in previous articles on American Triassic fishes, the 

 term in question is regarded merely as a synonym of Agassiz's 

 earlier defined genus, Semionotus. We pass on now to a con- 

 sideration of the different species occurring within the New 

 England area. 



Semionotus agassizii (W. C. Redfield). 

 (Plates I, II; Text-figure 8.) 



1841. Palcconiscus agassizii W. C. Redfield, Am. Journ. 



Sci., [1] xli, p. 26. 

 1850. Ischypterus agassizii Sir P. G. Egerton, Quart. Journ. 



Geol. Soc, vi, p. 10. 

 1856. Ischypterus marshi W. C. Redfield, Proc. Amer. 



Assoc. Adv. Sci., pt. 2, p. 188 (name only). 

 1888. Ischypterus agassizii J. S. Newberry, Monogr. U. S. 



Geol. Surv., xiv, p. 30, pi. 3, fig. 1. 

 1888. Ischypterus marshi J. S. Newberry, ibid., p. 28, pi. 2, 



fig. 1. 

 1903. Semionotus marshi G. F. Eaton, Am. Journ. Sci., 



[4] xv, p. 264, pi. 5, figs. 5, 9, 10, 12; pi. 6, 



figs. 1, 2. 

 1905. Semionotus agassizii C. R. Eastman, Ann. Rept. 



N. J. Geol. Surv. for 1904, p. 80, pi. 1; pi. 2, 



figs. 5, 9, 10, 12; pi. 3, figs. 1, 2; pi. 7, 8. 



A large and elegantly fusiform species, attaining a total length 

 to the base of the caudal fin of about 25 cm., in which the length 

 of the head and opercular apparatus is contained three and one- 

 half times. The maximum depth occurs between the paired 

 fins, where the number of longitudinal scale-rows is about twenty. 

 The number of transverse scale-rows, counting along the lateral 

 line, is about thirty-four. Scales everywhere large and thick. 

 The boat-shaped dorsal ridge-scale covering the base of the 

 dorsal fin anteriorly is rather small, rounded in front and not 



