368 Bulletin ^7, United States National Museum. 



teeth ; pectoral fin about as long as the head is high ; gill openings a 

 little less than eye ; postorbital part of head contained about 4 times in 

 trunk ; dorsal beginning over pectorals, consisting of very delicate rays ; 

 trunk contained at least 12 times in tail ; greatest depth of body about 

 equal to head without snout. Lateral line with one series of con- 

 spicuous pores. Color uniform black, jaws lighter. Deep sea ; known 

 from West Indies, mid-Atlantic, off Pernambuco. Also from Alaska, the 

 present description from a specimen taken by Dr. Gilbert off the coast of 

 Alaska, apparently referable to J. (jUl\, but agreeing with (jiinther's figure 

 of A. iiifans. (iiifans, immature.) 



Xemichthys ivfans* Gi'NTHEB, Aun. and Mag. Nat. Hist., 1878, 24, and in Voyage Challengor, xxii, 



264, 1887, mid-Atlantic, 2,500 fathoms. 

 ? Labichthyisf giUi, Be.vn, Proc. U. S. Nat. Mus., 1890, 45, east of Prince of \Vales Island, 



Alaska. (Type, No. 44239. Cull. Albatross.) 

 Avocettina infans, Jordan & Davis, 1. c, G55. 



170. LABICHTHYS, Gill & Ryder. 



Labichlhiis, Gill & Kydeb, Proc. U. S. Nat. Mus., 1883, 261, {carinalm). 



According to Goode & Bean the scantily described genus Lahidithys is 

 identical with AvoceUina.t The following is the original diagnosis: 



Nemichthyids with the head behind the eyes, contracted, with very 

 attenuated jaws, the branchiostegal membrane connected to the tliroat, 

 and the branchial apertures limited to the sides ; with small, conical teeth 

 in a band along the vomer, and otherwise dentition of Hemiehthya; a black 

 eiiidermis, and the tail abruptly truncated. (Gill & Ryder.) (/uid//, grip 

 or hold, correlated with Aa.i/f, forceps; ixf^i'^, fish.) 



a. Bidges bounding the median rostral groove converging backward in a median keel. 



CARINATUS, 603. 



aa. Ridges bounding the median rostral groove not confluent backward iu a ktel. 



ELONGATUS, 604. 



603. LABICHTHYS CARINATUS, Gill & Ryder. 



The ridges that bound the median rostral groove converging and form- 

 ing a carina along the median line in vertical from the anterior border of 

 the orbit; greatest height 34t^ in total length. Color black. (Gill &, 

 Ryder.) Dorsal beginning over base of pectoral ; vent close behind the 

 pectorals. (Bean.) Gulf Stream, 41° 13^ N., 65° 33'W.; a scantily described 

 species, not seen by us. (carinafiis, keeled.) 



Lahkhthys carinams, GiLL & Rtdek, Proc. U. S. Nat. Mus., 1883, 253, 255, 2C1, Gulf Stream; 

 Jordan & Davis, I. c, 656. (Type, No. 33369. Coll. Albatross.) 



* Nemichlhys infans, Gunther : Body much less elongate and eye much smaller than in Nemich. 

 thyx scalojMcca. Vent twice or thrice as distant from root of pectorals as is the latter from eye- 

 Eyo of moderate size, its diameter about J^ its distance from pectoral fin, and about twice inter- 

 orbital space. (Giinther.) 



f Lahiddliys giUi, Bean : Eye half length of postorbital part of head and % length of pectoral. 

 Postorbital part of head is l-^ upper jaw and ,\ of lower from angle of mouth. Dorsal beginning 

 nearly over end of pectoral. Vent distant from bead a ejiace equal to 4 times postorbital part 

 of head. Depth of body equals length of head without snout, 5',, of total. Dorsal rays very 

 short; longest anal rays g length of head. Lateral line of one series of large pores. Color 

 uniform black. Length 18J inches. Type from east of Prince of Wales Island, .'i5° 20' N., 136° 

 20' W., at 1,569 fathoms. (IJean.) Probably idintical with Avocetlina iiifans. (Named for Theo- 

 dore Gill.) 



I We should aecejit this view wete it not that the type of TMbichlliys is said to have the vent at 

 the throat as iu Xt'niichlhys. The posterior portion of the vent defiuee Avocdtina, 



