1910.] NATURAL SCIENCES OF PHILADELPHIA. 605 



aa. Cylindrosteus. Always a series of enlarged palatine teeth. 



e. Mouth-cleft, from snout tip to rictus, longer than rest 

 of head. 

 /. Scales 60-63. 



g. Eye lf-lf to opercle, 2\ in interorbital ; 



rictus width 3^-3$ in snout.... platostomus. 



gg. Eye 1^ to opercle, 2 in interorbital; rictus 



width 3 in snout scabriceps. 



//. Scales 55-58. 



h. Eye If— If to opercle, 2 in interorbital. 



i. Rictus width 4f in snout ...productus. 



ii. Rictus width 3^ in snout agassizii. 



hh. Eye 2\ to opercle, 2| in interorbital; 



rictus width 1\ in snout castelnaudii. 



ee. Mouth-cleft, from snout tip to rictus, shorter than 

 rest of head. 



j. Scales 57-60. 



k. Eye \\ to opercle megalops. 



kk. Eye 3 to opercle. .. tristoechus. 

 jj. Scales 51-54; eye 2 to opercle 



tropicus. 



Lepisosteus huronensis (Richardson). PI. XXXVIII, fig. 2. 



Lepidosteus otarius Cope, Proc. Acad. Nat. Sci. Phila., 1865, p. 86. "Platte 

 River, near Fort Riley." 



Head 2-£-3i; depth 3i-5| in head; D. 8, rarely 7 or 9; A. 9, fre- 

 quently 8, rarely 7 or 10; P. 12, often 11, rarely 7 or 10; V. 6, rarely 

 7 ; scales 62, frequently 63 or 64, rarely 60 or 61 ; predorsal scales 51 , 

 often 50, 52-54; scales around trunk middle 39, often 38, seldom 34. 

 35, 41-43; snout lf-lf in head; eye 1^-1| to opercle; interorbital 

 |-1 T V; length 200-710 mm. Warren County, Pa., 3; Battle Creek 

 in upper Mo. basin 1 ; Port Riley, Kan., 1 ; Wabash R., Ind., 1 ; Holston 

 R., Va. (dry head); also 6 dry heads and 4 dry skins without data. 

 No. 16,968, A. N. S. P., cotype of L. otarius Cope. Figure of Warren 

 County example. 



Sarchirus vittatus Raf. and S. argenteus Raf. are unidentifiable 

 young, possibly this species ? Lepisosteus longirostris Raf. may be 

 the adult, but is insufficiently described, and therefore I adopt 

 Richardson's name as the oldest. Lepidosteus semiradiatus Ag., L. 

 harlani Dum., L. smithii D., L. ayresii D., L. copei D., L. troostii D., 

 and Lepisosteus lineatus Thomps. agree in the large eye and may be 

 identical. L. bison DeK., Lepidosteus lesuerii Dum., L. elisabeth D., 

 L. lamarii D., L. piquotianus D. and L. horatii D., all have a smaller 

 eye. 



