54. PEBCiLiA. 255 



to the length of the head ; the diameter of the eye is one -sixth of the 

 latter. Denticulations of the prseoperculum visible on the inferior 

 limb only ; operculum with two feeble spines ; sub- and interoper- 

 culum without scales. The fourth dorsal spine longest. Coloration 

 uniform. {Cuv.) 



Port "Western (New Holland). 



53. EURO. 



Huro, Cuv. ^ Vfil. ii. p. 124 ; Richards. Faun. Bor. Amer. Fishes, p. 4. 



Six branchiostegals. AU the teeth villiform, without canines; 

 palatine bones ? ; tongue ? Two dorsals, the first with six, the anal 

 fin with three spines. No denticulations on the bones of the head ; 

 operculum with two flat obtuse points. Scales moderate. 



Lake Huron. 



1. Huro n%ricans. 



Cuv. Regne Anim. ; Ciw. 8f Val. ii. p. 124. pi. 17 ; Richards. Faun. 

 Bor. Amer. Fishes, p. 4 ; Dekay, New York Fauna, Fishes, p. 15. pi. 69. 

 f. 224 (cop.). 



^'^\h- ^-n- L-lat. 60-65. 



Height of the body equal to one-third of the total length, excluding 

 the caudal ; cleft of the mouth obliquely running upwards towards 

 the plane of the forehead. Caudal slightly notched. Coloration 

 uniform. 



Lake Huron. (Black Bass.) 



54. PERCILIA. 



Percilia, Girard, Proc. Acad. Nat. Sc. Philad. vii. 1854, p. 197, and 

 U.S. Naval Astron. Exped. to the Southern Hemisph. Zool. p. 235. 



Five or six branchiostegals. Maxillary teeth small, conical, with- 

 out canines ; palatine teeth none. Two dorsals, united at the base 

 only ; the first with nine spines, the anal with three. Operculum 

 without any spines ; a few minute spines along the Hmb of the prse- 

 operculum. Scales moderate. 



Rio de Maypu. 



1. Percilia gillissii. 

 Oirard, I. c. pi. 29. f. 5-9. 



D. 9 I 11. A.|. L. lat. 35. 



Snout short and rounded ; the upper maxillary reaching to the 

 vertical from the anterior margin of the eye. Light reddish or red- 

 dish brown, maculated with black. (Crir.) 



Rio de Maypu. 



