CYCLEPTUS 65 



Genus CYCLEPTUS Rafinesque 



Body elongate, little compressed, caudal peduncle very long; head 

 very small, short and slender; mouth small, inferior; lips tuberculate. 

 The skeleton is remarkable for deficiencies of ossification and other 

 features which mav indicate affinity with a primitive catostomoid 

 stock. Forward portion of chondrocranium strongty developed, the 

 trabeculse fusing anteriorly into a broad and thick ethmoid plate, which 

 is continuous in front with the bulbular cartilages of the end of the 

 vomer, and above with the broad girdle-like legmen cranii; bones of 

 skull somewhat heavy, their exposed surfaces more or less rough; pre- 

 frontals, meso- and ento-pter}^goids very spongy, and other bones 

 subject in varying degress to incompleteness of ossification; sutures 

 ven' distinct, never close and strongly joined, with cartilage between 

 the edges of the articulating elements in many instances ; configuration 

 of roofing bones of brain case and orbits much as in Ictiobus; nasal 

 foramen closed externally by a sieve-like plate; a small supraorbital 

 bone inteiA^ening between lateral wings of prefrontal and frontal ; 

 posterior fontanelle represented by a small opening at intercalation of 

 supraoccipital and frontals; anterior fontanelle present, notching 

 ethmoid and extending a short distance backward between frontals; 

 sub- and inter-operculum and branchiostegals rather small; phar}mgeal 

 bones narrow and spongy, the teeth from 25 to 35 in number, the lower 

 .ones somewhat compressed but strong, the remaining teeth weak, 

 diminishing rapidly in size upward; vertebras 49 in number, rather 

 heavy and poorly sculptured; ribs 13, short and weak; floating pairs 

 14, ver}^ slender and thread-like, their parapophyses (vertebrae 17 to 30) 

 short and stout and similar in form and size, with distal extremities 

 expanded and their free margins crenate; air-bladder in two parts, the 

 posterior wery long and slender and much tapered behind, furnished 

 interiorly with a spiral band of supporting cartilage; dorsal rays about 

 30, the first rays elongated, about half the length of the fin; scales 

 elongate, with a broad membranous posterior border; lateral line com- 

 plete, a peculiar and conspicuous membranous area about the posterior 

 terminus of each tube. Mississippi Valley; one species known. 



CYCLEPTUS ELONGATUS (Le Sueur) 

 (MISSOURI sucker; black-horse) 



Le Sueur, 1817, J. Ac. Nat. Sci. Phila., I, 103 (Catostomus). 



G., VII, 23 (Sclerognathus); J. & G., 121; M. V., 46; J. & E., I, 168; N., 50; J., 64; 

 F., 81; L., 12. 



Body elongate, little compressed and the back little elevated, depth 

 4 to 5 in length. Size large; length 2\ feet. Color dark, bluish black 

 about head; fins dusky to black; spring males almost black, the head 

 covered with small tubercles. Head ver^- small and slender, conic, its 

 length 5.8 to 6.4, width 8.2 to 8.8, depth 8.1 to 8.5 in length of body; 

 snout fleshy, tapering to the bluntly pointed muzzle, which extends 



