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 may indicate affinity with a primitive catostomoid 

 stock. Forward portion of chondrocranium strongly developed, the 

 trabeculae 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 girdledike legmen cranii; bones of 

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

 frontals, meso- and ento-pterygoids very spongy, and other bones 

 subject in varying degress to incompleteness of ossification; sutures 

 very 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 intervening 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; pharyngeal 

 bones narrow and spongy, the teeth from 2 5 to 35 in number, the lower 

 ones somewhat compressed but strong, the remaining teeth weak, 

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

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

 14, very 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 yen' long and slender and much tapered behind, furnished 

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

 50, 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 memliranous 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 A( Nat Sci. Phila., I. 103 (Catostomus). 



G., VII. 23 (Sclerognathus); J. & G., 121; M. V., 46; |. & E., I, 168; N., 50; 1 ,64; 

 1 ; , 81 ; L., 12. 



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

 1 io 5 in length. Size large; length 2h feet. Color dark, bluish black 

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

 covered with small tubercles. Head very small and slender, conic, its 

 length 5.8 to 6.4, width 8.2 to 8.8, depth S.i to 8.5 in length oi bodj , 

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



