DISCUSSION OF SPECIES AND THEIR DISTRIBUTION. 127 



passage througli tlie surface strata; and 1 am very much iucliued to tliiuk that the hitter 

 took phace. We have very little positive iiiformatiou as to the habits of these hshes, but 

 we know that they are commonly obtained near the surface in mid ocean; and ti'om their 

 structure we may infer that, like all deep, compressed fishes, they are slow swimmers, and 

 that they can with ease maintain a free position in the water, without the necessity of a 

 support, remaining as it were at a certain distance fi'om the surface. This may be observed 

 in a fish of our own seas with a similar elevated body, viz, the John Dory, in which, how- 

 ever, a rapid undulatory movement of the soft dorsal fin is almost unceasing. The great 

 develo])ment of the luminous organs, combined with the large eyes, indicates the nocturnal 

 habits of the fish, which would induce it to descend to a greater depth during the day- 

 tiukc. Also the firm structure of the bones disproves the bathybial habits oi ArgyropelectiuP 

 The following specimens have been obtained by the steamer Albatross: Cat. No. 331i96, 

 U. S. N. M., from station 2043, in 39° 40' N. lat., 68° 28' 30" W. long., at a depth of 1,4G7 

 fathoms; Cat. No. 33393, U. S. N. M., from station 2075, in 41° 40' 30" N. lat., 06° 35' W. 

 long., at a depth of 855 fathoms; Cat. No. 33495, U. S. N. M., from station 2003 in 42° 22' 

 N, lat., 00° 23' W. long., at a depth of 144 fathoms; Cat. No. 33500, U. S. N. M., from sta- 

 tion 2101 in 390 18' 30" N. lat., 68° 24' W. long., at a depth of 1,680 fathoms; Cat. No. 35467, 

 U. S. N. M., from station 2195 in 39° 44' N. lat., 70° 03' W. long., at a depth of ] ,058 fathoms; 

 Cat. No. 35534, U. S. N. U., from station 2208 in 39° 33' 71" N. lat., ICo 15' W. long., at a 

 depth of 1,178 fathoms; Cat. No. 35561, U. S. N. M., from station 2209, in 39° 34' 45" N. lat., 

 71^ 21' 30" W. long., at a depth of 1,080 fathoms; Cat. No. 38211, U. S. N. M., ft-om station 

 2728, in 30° 30' N. lat., 74'= 33' W. long., at a depth of 859 fathoms; Cat. 43855, U, S. N. M., 

 from station 2717, in 38° 24' N. lat., 71° 13' ^\. long., at a depth of 1,615 fathoms (Sp. nova?) ; 

 and a specimen from station 2565, in 38° 19' 20" N. lat., 69° 02' 30" W. long., at a depth of 

 2,009 fathoms. A single sjtecimen was obtained from the Grand Banks by a Gloucester 

 fisherman. 



ARGYROPELECUS D'URVILLII, Cuvier & Valkncienkes. 



ArgyropeUcus d'Urvillii, Cuvier & Valenciennes, Hist. Nat. Poiss., xxii, 405. — Gunther, Cat. Fish. Brit. 

 Mus., V. 1864, 386. 



The height of Mie body equals the distance between the gill opening and the root of the 

 caudal; tail nuich higher at its base than in A.hemigymnus; mandible without prominent 

 spine at its posterior corner; angle of the preoperculum with a spine directed downwards; 

 tail without spines. The pectoral fin does not extend to the hind margin of the trunk. 

 ( Valenciennes.) 



Eadial formula: B. 9; D. 9; A. 10; P. 10; V. 6. 



This form is known only from mid-Atlantic; it may possibly yet be found to be identical 

 with A. hemiyymnus. 



ARGYROPELECUS ACULEATUS, Valenciennes. 



ArgyropeUcus aeuleatus, Cm'lER & Valehciennes, Hist. Nat. Poiss., xxii, 406. — Gunthek, Cat. Fish. Brit. 



Mus., V. 1864, 386. 

 Argyropdccusacantkurus, Cuvier & Valenciennes, loc. cit., 408. 



The height of the body equals the distance between the posterior margin of the pre- 

 operculum and the root of the caudal; tail very slender. Mandible with a very obtuse 

 spine at its posterior corner; preoperculum with a spine direi'ted downwards. A double 

 row of spines along the lower side of the tail. ( Valenciennes.) 



B.9; D. 9; A. 14; P. 10; V. 7. 



This form has only been found at sea off the Azores. It may probably prove to be a form 

 of one of the better-known species. 



STERNOPTYCHIDES, Ogilby. 



Sternoptychidea, Ogilbv, Proc. Linna;an Society, New South Wales (2d ser.), in, 1313, 1888. 



"Pseudobranchiie luesent; head and trunk much elevated and compressed, the latter 

 passing gradually into the moderately long pedicle; the margin of the upper jaw formed by 



