COTTIDiE. — LXXIII. 149 



66. Preopercular spines small, mostly concealed by the skin; skin smooth 

 or prickly in or behind the axil only. (Potamocottus Gill.) 



406. C. richardsoni Agassiz. Miller's Thumb. Blob. 

 Muffle-jaw. Body rather stout, the head very broad; pre- 

 opercle with a short, sharp, straightish spine, turned upward and 

 backward, with 2 smaller spines below it. Olivaceous, much barred 

 and speckled. Head 3^; depth 4 to 6. D. VI to Vlll-ie. A. 

 12. V. I, 4. L. 3 to 7. Lake Superior to Ark., Ga., Md., and 

 Canada very abundant in springs, caves, cold lakes, and rocky 

 brooks. Very variable. The numerous varieties or nominal spe- 

 cies are hardly worthy of recognition by name. (To John Rich- 

 ardson, author of the " Fauna BoreaU- Americana.") 



aa. Palatine teeth, none ; V.I, 3; skin mostly smooth. (CottusA) 

 c. Anal rays IS or 14. 



d. Preopercular spine large, hooked upward. 



407. C. poUicaris (Jordan & Gilbert). Light olive, blotched 

 and spotted with black, but not speckled ; upper fins spotted. Eye 

 5^ in head. Head 3|; depth 4|. D. VII -19. A. 13. L. 5. 

 Lake Michigan. (Lat., thumb-like.) 



408. C. spilotus (Cope). Olive, everywhere closely speckled 

 with darker except on beUy ; sides barred with blackish ; fins 

 barred and spotted. Eye 4^ in head. Head 3^; depth 5. D. 

 VIII -17. A. 13. L. 3. Grand Rapids, Mich. (o-mXmTo'r, 

 spotted.) 



dd. Preopercular spine short, acute, turned obliquely upward. 



409. C. viscosus Haldeman. Stout, with many mucous pores ; 

 fins low. Olivaceous, body and fins mottled with dark ; 1st D. with 

 red edge. Head 8^ ; depth 4|. D. VI -18. A. 14. Penn. to Md. 



cc. Anal rays 11 or 12. 



e. Preopercular spine short, scarcely hooked. 



y. Preopercular spine bent upward and backward. 



410. C. gracilis Heckel. Body rather slender ; fins large. Olivar 

 ceous, mottled, 1st D. edged with red. Head 3^ ; depth 4^ to 5^. 

 D. VIII -16. A. 12. L. 4. N. Eng. and N. Y. (Var. gobioides 

 Grd., with robust body, and var. boleoides Grd., with slender body 

 and long fins, have been described.) (Lat., slender.) 



Xf- Preopercular spine directed backward and scarcely upward. 



411. C. hoyi Putnam. Slender; 9 prickly above; jaws nar- 

 rower and mouth smaller than in C gracilis ; another spine below 

 it turned downward, and one or two others still lower. Olivaceous, 

 speckled and barred. D. VI -15. A. 11. L. 2. L. Michigan. 

 (To Dr. Philo E. Hoy.) 



ee. Preopercular spine distinctly hooked. 



1 The species of this group have never been critically studied ; some of them are 

 doubtful, and most of them may prove to be mere varieties of Cottus gracilis. 



