"""isQo'"] PROCEEDINGS OF THE NATIONAL MUSEUM. 159 



vomer, with the clamping processes selliform and appressed closely to 

 the sides of the ethmo- vomer behind its head, with ledge-like exten- 

 sions within, and atteunated backwards. 



Mandible moderately stout; the dentary with the coronoid process 

 well developed near its posterior end; the articular little produced ex- 

 ternally in front of the condyle, but considerably extended backwards 

 and below. 



Teeth conic, in cardiform bands on the jaws and vomer. 



Lips thick, mostly with free lateral margins, but undifferentiated in 

 front. 



Tongue well developed and free at its anterior portion as well as sides. 



Periorbital bones moderately developed. 



Opercular apparatus well developed ; operculum lamelliform and ob- 

 long, inserted high up on the hyomandibular; suboperculum falciform, 

 bordering the operculum ; interoperculum large, partly covered by the 

 preoperculum ; preoperculuni well developed, lamelliform. 



Branchial apertures lateral vertical slit s in front of and lower than the 

 inferior rays of the pectoral fins. 



Branchiostegal rays in moderate number (about twelve), some at- 

 tached to the ceratohyal and others to the epihyals, quite robust and 

 much bowed. 



Dorsal, anal, and caudal confluent in one uninterrupted fin with the 

 rays readily- perceptible through the thin skin ; dorsal commencing far 

 behind the head and little before the anus ; anal close behind the anus ; 

 caudal prominent. 



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

 distinct, unbranched, and articulated. 



Branchial arches nearly complete, with well developed glossohyal and 

 urohyal, but with the first and second basibranchials only ossified ; the 

 first and second hypobranchials ossified, third and fourth cartilaginous; 

 ceratobranchials and epibranchials, of four pairs, ossified; pharyngo- 

 branchials of first and second pairs, rod-like ; of third and fourth pairs, 

 in close apposition and developed as dentigerous epipharyngeals; hypo- 

 pharyngeals oblong and closely apposed and superincumbent on a rudi- 

 mentary fifth arch, covered with cardiform teeth. Interbranchial slits 

 extended. 



There are numerous other characters which support the family distinc- 

 tion of the Anguillidfe, but the only ones that need be here added are 

 the separation of the two frontals, the oblique, forward trend of the 

 suspensorium, and the moderate development of the hyomandibular. 



Only one genus of the fiimily is known — that generally called An- 

 guiUa, but also by Bleeker and some others endowed with the name 

 Murccna. 



Anguillais generally ascribed by authors to "Thunberg," but without 

 any definite reference to place of publication. Agassiz, in his "Nomen- 

 clator Zoologicus," refers to "Anguilla, Thunb., Nuov. Mem. Stock., 



