MUSEUM OF COMPARATIVE ZOOLOGY. 221 



CYCLOTHONE, new genus. 



Numerous small specimens, in very bad condition, were received, belonging 

 to an undescribed genus of the family Sternoptychidec, or of some closely related 

 family not yet denned. 



Diagnosis. — Body long, somewhat compressed, apparently naked, covered 

 with dark pigment-cells, there being no scales. A series of luminous spots 

 along the lower sides of the body. Head conical, cleft of mouth very wide, 

 oblique, the lower jaw strongly projecting. The maxilla is long and slender, 

 anteriorly curved strongly upward, its outline sickle-shaped, closely connected 

 with the short intermaxillary. Maxillary and intermaxillary with a single series 

 of rather large acicular teeth, about every fourth one in the maxilla longer than 

 the average. Lower jaw with teeth apparently uniform in size, raking forward, 

 and with a few canines in front. A small patch of minute teeth upon the 

 head of the vomer. Palate smooth. Eye moderate, inconspicuous, apparently 

 covered with opaque membrane, causing a dull appearance. Gill opening 

 very wide, the branch iostegal membrane free from the isthmus. Gill raker- 

 long and slender, moderately numerous, more than twice as numerous below 

 as above the angle. 



Pseudobranchiae absent (branchiostegals not clearly made out, apparently 

 seven , eight, or nine). No air-bladder. All the fins well developed : the anal 

 large : dorsal and anal fins entirely on the posterior half of the body : no 

 adipose dorsal : caudal forked. 



41. Cyclothone lusca, new species. 



Body elongate, its greatest height contained 7§ times in its length to base of 

 middle caudal rays, its width being less than two thirds of its height. lt< 

 height at the ventrals is contained 8 1 - times in standard length : the least height 

 of tail is half that of the body at the ventrals. 



Head length contained 4$ times in body length, its width about one third 

 of its length. The intermaxillary is very short, extending to vertical from 

 posterior limb of anterior nostril. The maxillary is very strongly curved 

 downward, and has a short knob at its anterior extremity, not visible without 

 dissection. The maxillary extends backward to a distance from the tip of the 

 snout equal to the length of the head without the snout. The peculiar ar- 

 rangement of the teeth is described above in the generic diagnosis. Mosl of 

 those in the maxillary are inclined strongly forward. 



The long lower jaw, with the exception of the projecting tip. is included 

 within the upper jaw : its length is equal to the distance from the anterior 

 nostril to the end of the head. 



Eye circular, close to the profile, the interorbital area being very narrow 

 Its length is equal to that of the snout, and contained -even times in the 

 length of the head. 



Dorsal tin inserted at a distance from the tip of the snout equal to time 



