PROCEEDINGS OF UNITED STATES NATIONAL MUSEUM. 227 



note: on the ceratsshje. 

 By THEODORE GILL. 



Since the publication of the third volume of Giinther's " Catalogue of 

 the Fishes in the British Museum" (18G1), and the present author's Note 

 on the Pediculati (18G3), the then monotypic family of Ceratiidw has 

 received notable additions, and this year (1878) one genus or rather type 

 of hitherto doubtful character has been substantiated, and two new allied 

 ones added. All the representatives of the group appear to be inhabi- 

 tants of the deep or open seas. The relations of the genera seem to be 

 approximately as follows: — 



Synopsis. 



la. Mouth moderate ; cephalic spine with its basal element exserted and continuons 

 with the distal ; pyloric cceca developed (2). 

 2. A second dorsal spine typically developed; month with the cleft subvertical; 

 1st D. with few rays ; branchiai in2i pairs; branchial arches unarmed; 



skin with scattered spinigerous scutelloe Ceratiin^. 



3a. A second dorsal spine developed, and two fleshy tubercles behind it ; pec- 

 torals with nearly 20 slender rays Cerallas. 



3&. No second dorsal'spine developed, but two fleshy claviform tubercles exist- 

 ing as in Cer alias ; pectorals with about 10 slender rays Mancalias. 



lb. Mouth moderate ; cephalic spiue with its basal element subcutaneous, procumbent, 

 and at right or acute angle with the distal ; pyloric cceca none, 

 2a. A second dorsal spine developed ; branchiae in 2^ pairs ; branchial arches un- 

 armed ; body naked. 

 3. Body and head compressed; mouth with the cleft nearly horizontal, and 



mandibular articulation behind eye Onkihodin^. 



Oneirodes. 



26. No second dorsal spine developed; branchiiE in 12^ pairs; branchial arches 



armed wilh dentigeroas tubercles; body with scattered tuLercular 



scutellae. 



3a. Body and head compiessed; mouth with the cleft oblique; mandibular 



articulation under or behind eye Himantolopuin^e. 



4a. Body oblong oval; dorsal fin with about 9 rays and pectoral wi h 



about 12 ? ,. Himantolophns. 



46. Body short oval ; dorsal fin with 4 rays and pectoral with about 17. 



Corynolophus. 

 36. Body and head depressed ; mouth with the cleft vertical or inclined for- 

 wards ; mandibular articulation under or in advance of snout 



yEOiEONICIITIIYIXJi:. 



JJiyaiouichthtjs. 

 Ic. Mouth enormous; (cephalic spine with its basal element subcutaneous, procum- 

 bent, and at an acute anyle with its distal ?). 

 2. No second dorsal spine developed. Mouth with the cleft subvertical. 1st D. 

 with about 14 rays; branchia; in 2\ pairs; branchial arches un 



armed; skin naked Melanocetin^. 



Mdanocelus. 



CERATIIN^. 



CERATIAS. 



Ceratias, Kroijcr, Naturhist. Tidskrift, 2. roekko, b. 1, p. 639, 1844. 

 Type: C. Holbolli"A>o!/er. 

 Deep sea otf Greenland. 



