234 PROCEEDINGS OP THE ACADEMY OP [1886. 



aa. Snout projecting, subtubiform ; dorsal spines small, about 15 ; 

 innominate bones joined only at base ; body elongate ; sides 

 mailed. Spinachia. 5. 



1. PYGOSTEUS. 



Pyrjosteus (Brevoort MSS.) Gill, Cat. Fish. East Coast N. A., 39, 1861. 



(Not characterized); Canadian Naturalist, ii, 8; August, 1865 {occi- 



dentalis). 

 Oasterostea Sauvage, Revision dcs Epinoches, 29, 1874 {pungitius). 



This genus is cbaracterized by the presence ofl to 1 1 divergent 

 dorsal spines and by the weakness of the innominate bones. It 

 differs from Gaster-osteus also, in having the posterior margin of 

 the gill membrane free and by the less development of the spin- 

 ous armature. 



But a single species, variable in its characters, seems to be 

 known. It is widely distributed in the fresh and brackish waters 

 of northern regions. 



Analysis of Species of Pygosteus. 



a. Body extremely elongate and slender, deepest at ventral spines, 

 decreasing in height towards head and tail. Head long, 4 

 in length to base of caudal. Mouth large, very oblique ; 

 maxillary not reaching to anterior margin of orbit. Teeth 

 small, in a single series. Eye large, its diameter greater 

 than snout. Caudal peduncle keeled, slender and long, 

 about 5 in length to base of caudal. No bony plates along 

 side ; small plates extending along the bases of the anal 

 and soft dorsal. Post pectoral plate present, large and 

 faintly granulate. Scapula forming a triangular post oper- 

 cular plate ; operculum striate. All the surface bones very 

 weak, bones of scull granulate; innominate bones weak, trans- 

 lucent, thin in the median part. Gill openings extending to 

 below posterior edge of preopercle. Vertebrae (pungitius) 

 14 + 18. Caudal fin lunate, long and narrow. 



b. Ventral spines more than one-third of head. I). VII. to 

 IX-1, 9; A. 1, 8. Pungitius. 1. 



66. Ventral spines less than one-third length of head. D. X- 

 I. 10 ; A. I, 10. Brachypoda. 1 (a.) 



