DISCUSSION OF SPECIES AND THEIR DISTRIBUTION. 127 



passage through the surtace strata; and 1 am very much inclined to think that the latter 

 took place. We have very little positive information as to the habits of these fishes, but 

 we know that they are eoninionly obtained near the surface in mid-ocean; and from 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 from 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 imceasing. 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- 

 time. Also the firm structure of the bones disproves the bathybial habits of ArgyropeleciisP 

 The following specimens have been obtained by the steamer Albatros.s: Oat. No. ;}32i)6, 

 U. S. N. M.. from station 2043, in 30^ 40' N. lat., 08° 28' 30" W. long., at a depth of 1,4(57 

 fathoms; Cat. No. 33393, U. S. N. M., from station 2075, in 41° 40' 30" N. lat., 66o 35' W. 

 long., at a depth of 855 fathoms; Cat. N.>. 33495, U. S. N. M., from station 20C3 in 42^3 22' 

 N. lat., 06-= 23' W. long., at a depth of 144 fathoms; Cat. No. 33560, U. S. N. M., from sta- 

 tion 2101 in 390 18' 30" N. lat., 08° 24' W. long., at a depth of 1,680 fiithoms; Cat. No. 354G7, 

 U. S. N. M., from station 2195 in 39° 44' N. lat., 70° 03' W. long., at a depth of 1 ,058 fathoms; 

 Cat. No. 35534, U. S. N. M., from station 2208 in 39° 33' 71" N. lat., 16^ 15' W. long., at a 

 depth of 1,178 fathoms; Cat. No. 35561, U S. N. M., fr-om 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., from station 

 2728, in 36° 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' W. long., at a depth of l,(il5 fathoms (Sp. nova?) ; 

 and A specimen from station 25G5, in 38° 19' 20" N. lat., 69° 02' 30" W. long., at a depth of 

 2,069 fathoms. A single si>ecimeu was obtained fi'om the Grand Banks by a Gloucester 

 fisherman. 



ARGYROPELECUS D'URVILLII, Cuvier & Valenciennes. 



ArgyropelecMS d'UrinUii, Cuviek & Valenciennes, Hist. Nat. Poiss., xxii, 405. — Guntuei:, Cut. Fish. ISrit. 

 Mus., V. 1864, 386. 



The height of the body ecjuals the distance between the gill opening and the root of the 

 caudal; tail much higher at its base than in A.hcmlgymnus; mandible without iirominent 

 spine at its jiosterior 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. 

 ( ValencicKHCs.) 



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. hemUjymnus. 



ARGYROPELECUS ACULEATUS, Valenciennes. 



Argyi-opelecus aculcatus, Cuvier &, Valewciennes, Hist. Nat. Poiss., xxii, 406.— Gunthek, C.it. Fisli. Brit. 



Mus., V. 1864, 386. 

 Argyropelectis acanthurus, Cuvier & VjVI.enciennes, 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 directed downwards. A double 

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



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. 

 Sternopty chides, Ogilby, Proc. Linnfeau Society, New South Wales (IM ser.), in, 1313, 1888. 



"Pseudobranchiai present; head and trunk much elevated and compressed, the latter 

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



