^°l89o!"'] PROCEEDINGS OF THE NATIONAL MUSEUM 233 



rays readily perceptible throiigli the Ihiu skin ; dorsal comHieucing 

 nearly above or in advance of the basis of the pectorals ; anal com- 

 mencing iiuniediately behind the anus; caudal prominent. 



Pectorals well developed, nearer tbe breast than back, with the rays 

 distinct. 



Branchial arches nearly complete, with well-developed glossoliyal and 

 long slender urohyal,* but with first and second basibranchials only os- 

 sified; the hypobranchials of the first three arches well developed and 

 ossified, of the fourth and fifth suppressed; ceratobranchials and epi- 

 branchials of four pairs ossified; pharyngobranchials of first arch, rudi- 

 mentary ; of second, moderate; of third, expanded and connected also 

 with fourth; of fourth, t developed as lamelliform epipharyngeals covered 

 with cardiform teeth; hypophar^^ugeals elongated linguiform bones cov- 

 ered with cardiform teeth and dislocated so as to cover the basal por- 

 tion of the ceratohyals of the fourth pair. 



Interhranchial slits extended. 



The characters which appear to distinguish the Murwnesoces best from 

 the Anguillids andCongrids or Leptocephalids are the low position on the 

 hyomandibular of the condyle for the operculum; the slender branchial 

 arches and the development and position of the hypopharyngeals and 

 epipharyngeals; the union of the opposite branchiostegals by the inferior 

 branchiostegal membrane, and the want of freedom of the tongue. 

 Whether the other genera that have been closely associated with Mu 

 rwnesox {Hoplunnis, Oxyconger, Neoconger, Nettastoma, and Saurenchelys) 

 are related to the family can only be determined by an examination of 

 their skeletons. The si)ecies combined under the uame Murccnesox are 

 the only ones certainly possessed of the characters provisionally as- 

 signed to the family. The species generally united under the generic 

 designation differ considerably, and have been distributed by Dr. 

 Bleelcer under two genera. It will be convenient at least to recognize 

 them as subgenera, but a section not yet isolated, distinguished by the 

 simply conic teeth, is as worthy of distinct rank as the two already 

 named. Three sections of generic or subgeueric rank may therefore 

 be recognized, viz : 



* The basal half of the urohyal is invested in the membrane between the opposite 

 branchiostegal arches, and from the lower surface, at the place of emergence up- 

 wards from the membrane, arises the ligament connecting with the anterior points 

 of the scapular arch. 



t It is inferred that the dentigerous epipharyngeal is the fourth pharyngobranchial, 

 from the fact that it is the fourth pharyngobranchial or second epipharyngeal which 

 is the largest in the Anguillidw. In that case it is the the third pharyngobranchial 

 which has widened and developed a process for the fourth epibrauchial in Mtinene- 

 sox, Avhilo the epipharyngeal is entirely dislocated from its normal position and its 

 base of attachment transferred to the second epibrauchial and third pharyngobran- 

 chial. 



