78 (IHECK LIST OF THE 



joined to the isthmus anteriorly. Gill rakers tubercle-like, dentate. 

 Pseudobranchia^ obsolete. Gills four, a small slit behind the fourth. 

 Branchiostegals six. Scales moderate, strongly ctenoid, adherent. Lateral 

 line imperfect or wanting-. Vent always anterior, its position varying- 

 with age, from just behind the ventral fins in the young to below the pre- 

 opercle in the adult. Dorsal fin single, median, high, wuth but three or 

 four spines, which are rapidly graduated, the first being very short. Anal 

 small, with two slender spines ; ventral fins thoracic, with a very short 

 spine, the number of soft rays usually seven ; caudal fin rounded behind. 

 .•\ir bladder simple, large, adherent to the walls of the abdomen. Pyloric 

 Cceca, about twelve. 



Genus APHREDODERUS. (Pirate Perches.) 

 The characters of the genus are included above. 



(83) Pirate Perch. 



(Aphredoderus sayanus.) 



Body moderately stout, oblong, somewhat compressed posteriorly. 

 Scales ctenoid. Dorsal fin continuous, its origin much in advance of the 

 middle of the total length ; the anterior spines much the shortest. Mouth 

 large for the size of the fish, the lower jaw somewhat longer than the 

 upper; the maxilla reaches to front of eye; jaws, vomer and palatine bones 

 with villiform bands of teeth. Lateral line wanting. Caudal rounded. 



D. IIL, II ; A. IL, 6. Scales on lateral line, 48 to 58. 



Colour, variable, sometimes olivaceous, at other times dark brown 

 with numerous dark punctulations ; a dark bar at the base of the caudal 

 followed by a light one. It reaches about four inches in length. 



I include this species, though there are no Ontario records of its 

 orcurrerice here known to me. It should, however, be found in the streams 

 of the Niagara district and at the western end of Lake Erie. It frequents 

 sluggish streams and ponds in which aquatic weeds abound, and is 

 remarkable because the position of the vent varies with age. In the 

 young it is behind the ventrals, while in the adult it is in the throat. 



Suborder PERCESOCES. 



Ventral fins abdominal, each of one spine and five rays; brancliial 

 arches well developed, the bones ■ all present except the fourth superior 

 branchihyal. Third superior pharyngeal much enlarged ; lower pharyn- 

 geals distinct. Scales cycloid. Pectorals elevated, about on a level with 

 the upper posterior angle of operculum; spinous dorsal usually present. 



