MUSEUM OF COMPARATIVE ZOOLOGY. 219 



of head slightly less than length of operculum, and 9^ times in length of body 

 (12 in A. Bairdii). 



Length of snout half that of mandihle, which is one sixth of total length (£ in 

 A. Bairdii). Diameter of orbit in total length of body 10£ times (18 in 

 A. Bairdii), Z\ in head (about 4£ in A. Bairdii). 



The insertion of the dorsal is immediately above the vent ; the distance of its 

 origin from the base of middle caudal rays equal to one third of distance from 

 same to anterior margin of orbit, and at a distance from the snout much greater 

 than two thirds the total length of body (about equal in A. Bairdii). The 

 length of its base is equal to one eighth of total length. 



The origin of the anal is under the second ray of the dorsal ; its length of 

 base is slightly more than one seventh of the body length, and is equal to the 

 height of the body at the vent. 



The ends of the dorsal, anal, and caudal rays are broken off in the specimen 

 before us. 



Distance of pectoral from snout, equal to J of the body length (slightly more 

 than \ in A. Bairdii) and 4£ times least height of tail (3 in A. Bairdii). Its 

 length equal to the diameter of orbit and contained 10^ times in total length 

 (10 in A. Bairdii). The origin of the pectoral is close behind the end of the 

 opercular flap, while in A. Bairdii it is separated therefrom by four rows of 

 scales. 



Distance of ventral from snout considerably less than twice the length of the 

 head. Its length, probably, about one sixth that of the head. 



Radial formula : D. 15 ; A. 17 ; C. 19 ; P. 11 ; V. 1, 5 ? 



L. lat. 90. 



Dentition as in A. Bairdii. 



Color dark, head and fins nearly black. 



HALOSAURLELE. 



37. Halosaurus macrochir, Gunther. 



Halosaurus macrochir, Gunther, Ann. and Mag. Nat. Hist., 6th Ser., II., 1878, 



p. 251. 



H. macrochir was described by Dr. Gunther from specimens obtained by 



H. M. S. " Challenger,'' in the Atlantic, at a depth of L090 fathoms, and mid- 

 way between the Cape of Good Hope and Keiguelen's Land, at a depth of 

 1375 fathoms. 



Specimens were obtained by the " Blake " at the following stations : — 



