SYNOPSIS OF THE CYPPJNIDiE OF PENNSYLVANIA. 



381 



spot on middle of front dorsal rays, and faint one at base of caudal ; parietal region broad, flat, temporal angled ; 

 eye 3.5 in length head, whieh enters 4.5 times to base caudal. tuditanus.* 



Scales 5 — 36 — 4, 15 rows anterior to dorsal fin, which is equidistant between base of caudal and end of muz- 

 zle ; muzzle very obtuse, mouth moderate ; sides silvery ; often a median dorsal band, no spot on dorsal fin ; parie- 

 tal and temporal region rounded; eye larger, three times in head, which is four times to base caudal, stramineus. 



" Mouth protractile downward ; snout pointed; a deep black band from nape to base of dorsal, round both sides 

 of it to median line again ; olive, sides silvery, a deep rose-colored spot at base of dorsal fin." (Agassiz.) 



DORSALIS. 



Scales 5 — 31-3 — 3, 13 rows in front of dorsal, a dorsal line and burnished plumbeous lateral band, with blackish 

 pigment below ; teeth 4 — 4 ; eye one-third longer than deep ; head one-fifth total, front decurvod, obtuse, mouth 

 horizontal, mandible shorter; caudal peduncle slender, its median depth one-fourth length from first anal ray, 

 A. 7. PROCNE. 



aa. Pectoral fins attaining vontrals. 



Tload flattened, elongate; eye contained three and one-third times; head to base caudal three and three fourths ■ 

 scales 4 — 34 — 3; dorsal length half from its first ray to base caudal; caudal peduncle slender; no dorsal band; a 

 darkish lateral. VOLUCELLUS. 



"Head broad, nearly one-fourth length; snout short, broad; eye one-third head, line of margin reached by 

 maxillaries; caudal peduncle slender." (Agassiz.) gracilis. 



G. Teeth 4 — 4; mouth obliquely descending; lateral line complete. 

 Scales 7— 44— 4, blackish-edged above lateral line, 21 rows in front of dorsal, which is nearer caudal than end 



* llybopsis tuditanus, m. sp. nov. 



This is an abundant species, and has so much the aspect of Ilyborhynchus notatus, as to 

 bo readily mistaken for it; its resemblance consists in the broad flat head, and angulated 

 temporal region, size of scales, rounded muzzle, and even in dentition, but the latter differs 

 toto coelo in the structure of tin: alimentary canal and dorsal fin, form of the scales and 

 the tubercles, and great thickening and obtuseness of the muzzle. 



Cranium flat above, temporal width 1.5 in length above, and equal length from end muzzle to posterior margin 

 of orbits. Dorsal fin lower than usual, height anteriorly equal its basis, six-sevenths of to equal height of anal, 

 and three-fourths length of caudal ; basis of anal three-fifths basis dorsal. Greatest depth 5.33 times to origin of 

 caudal. Muzzle rounded, very obtuse in profile, broad as two-thirds parietal width. Mandible short, outline 

 slightly angulated in front. 



Total length 3.1 in. ; from end muzzle to first dorsal ray 1.375. 



Olivaceous above, dorsal scales narrowly black-edged ; no vertebral band ; sides and below silvery. The types 

 of this species were procured in the Detroit lliver ; these with numerous others, from the St. Josephs, exhibit a 

 dark lateral band extending from the end of the muzzle to the base of the caudal fin, especially dark on the oper- 

 culum. Specimens from the Wabash at Lafayette, Indiana, where I have taken it in large numbers with the 

 Hybognathus nuchalis, Agassiz, do not exhibit this lateral line. In all is a basal caudal spot, and dark spot at 

 middle of anterior dorsal rays, the latter very indistinct in young specimens. 



