PROCEEDINGS OF UNITED STATES NATIONAL MUSEUM. 227 



NOTE OIV THE CERATIIDJE. 



By THEODORE GILL.. 



Since the publication o? the third volume of Gunther's « Catalogue of 

 the Fishes in the British Museu^ » (18G1), and the present author's Note 

 on the Pediculati (18G3), the then ^nonotypic family of Ceratiidce has 

 received notable additions, and this year /{ 8 78) 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 conth*, ong 

 with the distal ; pyloric cceca developed (2). 

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



1st D. with few rays ; branchiae in 2| pairs ; branchial arches unarmed ; 



skin with scattered spinigerous scutellae Ceeatiinje. 



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

 torals with nearly 20 slender rays Ceratias. 



36. No second dorsal spine developed, but two fleshy claviform tubercles exist- 

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



16. Mouth moderate ; cephalic spine 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 Oneirodin^e. 



Oneirodes. 



26. No second dqrsal spine developed; branchiae in pairs; branchial arches 

 armed wilh dentigerons tubercles; body with scattered tubercular 

 scutellae. 



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



articulation under or behind eye Himaxtolopiiin^e. 



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



about 12 ? Himantolopluis. 



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 



-iEGJSOXICIITIIYIXJE. 



JEgcconichthys. 



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

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

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



with about 14 rays; branchiae in 2£ pairs; branchial arches un- 

 armed; skin naked Melanocktin.e. 



Mdanocctus. 



CERATIINiE. 

 CERATIAS. 



Ceratias, Kroycr, Naturhist. Tidskriffc, 2. raekko, b. 1, p. 639, 1844. 

 Type : C. Holbolli Kroyer. 

 Deep sea off Greenland. 



