112 CONTEIBUTIONS TO NORTH AMERICAN ICHTHYOLOGY IV. 
a. Basal br.incliihyals 2; pharyngeal teeth numerous, pectinate; maxillaries 
forming i^art of the margin of the upper jaw Catostomid/E, 30. 
aa. Basal hranchihyals 3 ; iiharyngeal teeth few ; margin of upper jaw formed by 
premaxillaries alone CYPniNiD.E, 31. 
**■ Brain case not produced between orbits ; basis cranii double, sometimes with mus- 
cular canal ; 4 to 1 superior pharyngeal bones ; lower pharyngeals not falci- 
form; 3 basal brauchihyals ; teeth in jaws often present. {Charadni.) 
ClIARACIXIDiE, 32. 
Family XXX.— CATOSTOMID^. 
{The Sucker s.\ 
Body oblong or elongate, usually more or less compressed. Head 
more or less conoid. Opercles normally developed. Is'ostrils double. 
No barbels. Month large or small, usually protractile and with lieshy 
lilis. Margin of niiper jaw formed in the middle by the small liremax- 
illaries, and on the side by the maxillaries. Jaws toothless. Lower 
liharyngeal bones falciform, armed with a row of unmerous comb-like 
teeth. Branchiostegals 3. Gill membranes more or less united to the 
isthmus, restricting the gill-openings to the sides. Gills 4, a slit be- 
hind the fourth. Pseudobranchige i)reseut. Scales cycloid, large or 
small. Lateral line deenrved, sometimes wanting. Head naked. Fins 
not scaly. Dorsal fin comparatively long (of 11-50 rays), without true 
spine. Anal fin short. Caudal fin more or less forked. Yentrals ab- 
dominal, with about 10 rays. Pectoral fins x^laced low, without spine. 
No adiifose fin. Belly not serrated. Alimentary canal long. Stomach 
simple. No iiyloric coeca. Air-bladder large, divided into two or three 
parts by transverse constrictions, not surrounded by a bony capsule. 
Genera 14 or fewer; sxiecies about GO; inhabiting the fresh waters of 
North America, two s^iecies in Eastern Asia. They are not much valued 
as food fishes, the flesh being flavorless and full of small bones. 
{Cyprinida, group Catostomina Giintber, vii, 12-24.) 
* Dorsal fin elongate, its developed rays 25-50 in number ; air-bladder in two parts, 
t Fontauelle ijresent ; body ovate ; scales large. {Bubalichthyince.) 
a. Dorsal rays 24-33. 
b. Mouth large, terminal, jirotractile forwards ; lips thin ; pharyngeal bones and 
teeth weak Ictiobus, 59. 
bb. Mouth smaller, inferior, xu'otractile downwards. 
c. Pharyngeal bones strong, the teeth comparatively coarse and large, in- 
creasing in size downwards Bubaliciitiiys, 60. 
cc. Pharyngeal bones narrow, with the teeth thin and weak.. Carpiodes, 61. 
ti Fontanelle obliterated by the union of the parietal bones ; body elongate. ( Cyclcp- 
tiiice.) 
d. Mouth small, inferior, with thick papillose lips ; scales rather small. 
Cycleptus, 62. 
