"""im"] PROCEEDINGS OF THE NATIONAL MUSEUM. 301 



angular well developed, forming the posterior border of the mandible 

 and extending into an external notch between the dentary and articular. 



Teeth mostlj^ curved, conic or bent backwards, and rather blunt ; 

 moderate and uniserial on the jaws except in front, where they extend 

 on a short row on each side of the symphysis of the upper jaw forwards 

 and where they extend in a projecting group in the dentary; enlarged 

 and uniserial on the vomer and palatines. 



Lips membranous ; the lower reverted over the jaw. 



Tongue well developed ; free in front and on the sides. 



Periorbitals incomplete, the preorbital alone (apparently) being de- 

 veloped ; that bone has a wide expanded surface in front and its upper 

 edge united with the external edge of the nasal, while the lower edge is 

 applied to the intermaxilline and its posterior edge about the middle 

 emits a long linguiform process backwards. 



Opercular apparatus well developed ; operculum lamelliform and 

 semihastiform, the upper edge being nearly straight and the lower pro- 

 jecting downwards; snhoperculum rather wide below and projecting 

 backwards beyond the operculum ; interoperculum thickened and con- 

 nected behind with the suboperculum and in front with the angular 

 of the lower jaw; preopercuhim well developed and closely appressed to 

 the suspensorium ; a triangular vacuity intervenes between the oper- 

 culum, interoperculum, and preopercuhim. 



BrancMotr ernes confluent into a jingle external transverse lunate 

 lissure in the thoracic region. 



Branchiostegals six, segregated into two groups ; one, of two compara- 

 tively slender rays arising from the lateral surface of the ceratohyal 

 near the edge; the other, of four stouter rays arising from a groove 

 hollowed out of the outer surface of the ceratohyal and epihyal. 



X>orsfl?/s reduced to a fold on the tail; caudalis rudimentary ; other 

 fins suppressed. 



Branchial apparatus peculiarly modified; branchial arches deflected 

 backwards and with the ceratohyals of the fourth at their tips con- 

 nected with articular surfaces on the proximal edges of the proscapulae, 

 and with the arches segregated in two groups, the first and second 

 approximated and the third and fourth approximated and remote from 

 the anterior; with a well developed glossohyal and a short hastiform 

 urohyal, and only the first basihyal ossified ; the hypohyals of the first 

 arch normally developed and connected with the basihyal: of the second 

 arch, normal and connecting with each other ; of the third shoved out 

 of place sideways, and of the fourth shoved together so that the poste- 

 rior sides meet in the middle and the bones partly intervene between 

 the preceding hypobranchials of the third arch ; ceratohranchials of 

 four arches ossified ; epibranehials of first arch suppressed, of other 

 arches developed and deflected downwards at acute angles with the 

 ceratohyals; of the second arch with a broad base, corresponding to 

 the expanded tip of the ceratohyal ; of the third and fourth arches 



