3i8 Field Museum of Natural History — Zoology, Vol. VII. 



ee. Premaxillaries protractile. Cottogaster, 322 



dd. Median line of belly with ordinary scales, or the entire ventral 



surface naked, never with large scales or plates; separation of 



ventrals less than their width at base. 



f. Maxillary adnate to the preorbital; premaxillary protractile 

 downward ; mouth small, overhung slightly by the blunt snout. • 



Diplesion, 323 

 ff. Maxillary free from the preorbital. 



g. Premaxillaries protractile. 



h. Body covered with scales; snout blunt or bluntish. 



Boleosoma, 324 

 hh. Dorsal and ventral regions with few or no scales; snout pointed. 



Ammocrypta, 326 

 gg. Premaxillaries not protractile, 

 i. Lateral line more or less developed; scales small, more than 40 



in lateral series. 

 j. Lateral line straight. Etheostoma, 327 



jj. Lateral line arched anteriorly. Boleichthys, 330 



ii. Lateral line entirely wanting; scales larger, less than 40 in 



lateral series. Microperca, 331 



Genus Stizostedion Rafinesque. 



Pike-perches. 



Body elongate, fusiform; back broad; head large with pointed 

 snout; preopercle with antrorse serrae; opercle with one or more 

 spines; teeth on jaws and on palatines in villiform bands, a few en- 

 larged and canine-like; pseudobranchiae well developed; pyloric 

 cccca 3 to 8; caudal fm lunate. 



a. Spinous dorsal with 2 or 3 rows of large black spots; pyloric 

 cceca 5 to 8, unequal, the longest shorter than the stomach. 



canadense, 318 



aa. Spinous dorsal with a single large black spot on last two 



membranes; pyloric coeca 3, subequal and as long as stomach. 



viireum, 319 



SUzostedion canadense. (vSmith) Saugkk; Sand 1'ike; Gray Pike. 



Head 3.4 to 3.6; depth 5.2 to 5.5; D. x to xiii — 17 to 19; A. 11, 

 II or 13; scales 85 to 91. 



Body elongate, slightly ccjinprcsscd; head large, cU-prcsscd; in- 

 tcrorbital space flat; mouth large, the maxillary reaching past i)upil; 



