'^l89o'"'] p, '. PROCEEDINGS OF THE NATIONAL MUSEUM. 167 



liiiid tluxkmttter edge of the opercuUim; iuteropercalaiu small, between 

 the suboperculuin a.iid preoperciilum; preoperculam small and with 

 miiciferous pores. 



Branchial apertures lateral aud roundish or irregular, generally little 

 nearer the breast than back. 



Branchiostegal rays in moderate number {9—x), concentrated back- 

 wards and confined to the epihyals, very slender and much bowed. 



Dorsal, anal, and caudal, when developed, confluent in one uninter- 

 rupted fin, with all the rays invested in the common integument, and 

 imperceptible without dissection ; dorsal diversiform, generally com- 

 mencing near the head, but sometimes atrophied ; anal generally com- 

 mencing near tbe anus, but sometimes atrophied; caudal always feebly 

 developed ; pectorals generally absent, rarely developed.* 



Branchial arches incomplete, without a glossohyal or urohyal, but with 

 the ceratohyals connected directly with the symphysis of the mandible 

 by a ligament ; with all the basibranchials and hypobranchials ob- 

 solete, the ceratobranchials being united with common cartilage be- 

 low ; ceratobranchials and epibranchials of the first, second, and third 

 arcbes very slender, of the fourth arch very robust, the ceratobran- 

 chials of the fourth arch dislocated upwards aud apposed to thehypo- 

 pharyngeals, as are the epibranchials to the epi pharyngeals; pharyngo- 

 branchials lost, except one pair which are developed as elongated denti- 

 gerous epipharyngeals ; hypopharyngeals elongated, superposed on the 

 fourth pair of ceratobranchials as are the epipharyngeals on the same 

 pair of epibranchials, the arch thus constituted forming a pair of 

 pharyngeal jaws, behind which is a slender fifth arch ; the pharyngeal 

 teeth acute and in one or few rows. Interbranchial slits narrow. 



Numerous other osteological peculiarities distinguish this type, but 

 those now given will sufficiently differentiate it from any others. 



Inasmuch as there are certain discrepancies between the description 

 here given and the characteristics assigned to the same type by Pro- 

 fessor Cope, an explanation seems to be demanded. 



Professor Cope has defined the group constituted by the Murwnidce 

 as an order in the following terms : 



COLOCEPHALI. 



Parietals largely in contact ; opercular bones rudimental ; the prseoperculum gener- 

 ally wanting.! Premaxillary rudimental or wanting ; ethmoid very wide. Sym- 

 plectic, maxillary, pterygoid, basal-branchihyal, superior and inferior pharyngeal 

 bones all wanting, except the fourth superior pharyngeal. This is jaw-like and sup- 

 ported by a strong superior branchihyal ; other superior branchihyals wanting or 

 cartilaginous. t 



* Myroconger with pectoral fins is placed by Dr. GUnther (Cat. Fishes B. M., v. 8, p. 

 93) in the section of Murcenidw engyschistcc, characterized by the fact that " the bran- 

 chial openings in the pharynx are narrow slits," and otherwise composed of typical 

 MurcBnidce. 



t Pterygoids rudimental or wanting. — Proc. A. A. A. S. 



t Trans. Phil. Soc, n. s., v. 14, p. 456, 1871. See also Proc. Phil. Soc, v. 13, 1873, 

 p. 25. 



