1885.] ° [Cope. 



character of the anterior dorsal vertebrae. From these it appears that the 

 genus is Isospondylous and not Plectospondylous. 



Char. gen. Dorsal fin small, above the anal, which is moderate. Pecto- 

 ral fin with several superior rays thickened and robust. Caudal fin fur- 

 cate. Ventrals small. No ventral or dorsal scuta. Scales much attenua- 

 ted. No basilar interneurals or haeinals. 



This genus may belong either to the Hyodontidm or CMrocentridm so far 

 as the characters given by authors are concerned, since the only distinc- 

 tions given are found in the soft parts. I have pointed out* that the parie- 

 tals are in contact, and the caudal fin embraces two vertebrae in the Hyo- 

 dontidcB, while in the Chirocentridce the parietals are separated by the supra- 

 occipital, and there is but one caudal-fin vertebra as in the Clupeidm. I can 

 only observe the caudal fin in Chiromystus, and find that it includes two 

 vertebrae, as in the Hyodontidm. 



Char, specif. The form is rather elongate. The depth of the longest 

 ribs, and vertebra corresponding, enter the length, exclusive of the head 

 and caudal fin, four and a third times. Vertebrae, Abd. 28 ; C. 22. The 

 anterior dorsals are obtained by counting the ribs, and three are added to 

 the caudals visible, in order to fill up an interruption caused by fracture. 

 The centra are longer than deep, and have two lateral longitudinal fossae, 

 bounded above and below by a narrow rib, and separated by a flattened 

 rib. 



The posterior part and apex of the dorsal fin are wanting, so that its 

 characters cannot be given, except by stating that the rays are slender 

 and weak. The anal fin is injured at its posterior extremity, but by 

 counting the interhaemal bones I find the rays to number sixteen. The 

 four superior pectoral rays are very robust, the inferior most so. The 

 three upper are preserved, and it can be seen that they are compressed 

 and smooth, and not segmented. The caudal fin is very deeply forked, 

 and the lobes are long. Each one consists of six strong external rays, 

 besides the fulcral rays, and a number of very fine rays on the inner side 

 of these, giving each lobe a narrow form. The scales are extremely 

 attenuated, and cannot be counted. The ventral fins are quite small, and 

 the rays may not all be preserved, although those that are visible are in 

 place. They number only four. 



Measurements. M. 



Length of vertebral column 310 



" " a lobe of the caudal fin 100 



" from base of ventral to base anal 081 



" " " anal to base caudal 085 



" " " " dorsal to base caudal 063 



" superior spine pectoral fin 065 



of ventral fin 027 



Diameters of last abdominal vertebra \ longitudinal. .. .008 



c vertical 0075 



• Proceedings Anier. Assoc. Adv. Sci., Vol. xx, p. 333. 



