318 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 Stizostedioii Rafmesque. 

 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 

 coeca 3 to 8 ; caudal fin 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 cceca 3, subequal and as long as stomach. 



vitreum, 319 



Stizostedion canadense. (Smith) SAUCER; SAND PIKE; GRAY PIKE. 



Head 3.4 to 3.6; depth 5.2 to 5.5; D. x to xm 17 to 19; A. n, 

 ii or 12; scales 85 to 91. 



Body elongate, slightly compressed; head large, depressed; in- 

 terorbital space flat; mouth large, the maxillary reaching past pupil; 



