126 DEEP-SEA FISHES OP THE ATLANTIC BASIN. 



spines bemj:f prolonfred beyond the iimscles, formiiiii' a triaiignlar osseous plate. Adipose 

 tin rudinientai-y; anal fin short; caudal forked. Gill opening- wide; outer brancliial arch 

 extending forward to behind symphysis of lower jaw and with very long gill rakers; bran- 

 cUiostegals nine; pseudobrauehiaj present; air bladder present. Pyloric appendages 

 four. {GUnther,) 



ARGYROPELECUS IIEMIGYMNUS, Cocco. (Figure 147.) 



Argijropdecm hemigymniis, Cocco, in Gioiii. So. Sic, 1829, faso. 77, 146. — Bonaparte, Fauna Italica. Pesci. 



foxt. — CiiviER ami Valenciennes, Hist. Nat. Poiss., xxii, 398. — GCnther, Cat. Fish. Brit. Mus., v. 



385. — (Uialleuger Report, xxu, 167. — Vaillant, Exp. Sci., Travailleur et Talisman, 103. 

 Sternoplijx heniu/i/mniis, Valenciennes in Cuvier Regue Animal, 111., Poiss. pi. 103, lig. 3. — GooDE and 



Bean, Bull. Mas. Coiiip. Zoijl. v, 10, 220. 

 Sternoplyx nudiierranca, Cocco, iu Giorn. II Faro, 1838, iv, 7, fig. 2.— Bonaparte, Fauna Italica, Pesci. fasc. 



xxvii, figure. 



Height of the body equals the distance between the gill opening and the caudal 

 base; posterior angle of mandible and angle of th« prseoperculum, each with a small trian- 

 gular spine ; tail slender, without spines. Pectoral reaching nearly to insertion of the anal. 



Eadial formula: B. 9; D. 7-8; A. 11; P. 9; V. 5. 



A. hemigymnus, is according to Giinther, common in the Mediterranean and neighbor- 

 ing parts of the Atlantic, and frequently caught at night in the surface net. During the 

 cruise of the Porcupine an adult example was obtained between Shetland and Faroe, at a 

 depth of 180 fathoms. Giinther concludes that this fisli is of nocturnal habits, living dur- 

 ing the day at a depth below the surface which varies according to circumstances. The 

 French expedition obtained it in the Gulf of Marseilles in 1,0G0 meters; in the Gulf of 

 Gascony iu 74:1-1,.534 meters; off the Canaries in 1,200 meters; off the coast of Portugal, in 

 950-1,100 meters, and off the coast of Morocco in 1,123 meters. 



This form, though usually very rare in the Mediterranean, sometimes is found in such 

 abundance that it is evident that in certain localities and depths it must be one of the 

 commonest of forms. Giglioli obtained iu September, 1878, at Messina, over seven hundred 

 in three days, brought to the surface by the swift current passing through the Straits. 



Two specimens of this species were obtained by the Blake, from Station cccxv, in 32'^ 

 18' 40" N. hit., 7SO 43' W. Ion., at a depth of 225 fathoms. One specimen (No. 31709, U. S. 

 N. M.) was takeuby the Fish Hawk from station 1112, in 39° 56' N. lat., 70° 35' W. Ion., at 

 a depth of 245 fathoms; and one by the Albatross from station 2117, in 15o 24' 40" N. lat., 

 63° 31' 30" W. Ion., at a depth of 083 fathoms. 



A species closely similar was taken by the Investigator in the ludiau Ocean, station 118, 

 in 103 fathoms. (Alcock, Ann. and Mag. Nat. Hist., 1891, ii, 126.) It may be called A. 

 AlcocJci. 



ARGYROPELECUS OLFERSII (Cuvier), C. and V. (Figure 148.) 



Sternuptyx Olfcrsii, CuviER, Rfegne Anim., 2d edit., li, 316, pi. xiii, fig. 2.— DOben and Koren, in Vet. Akad. 



Haudl., 1844, 80, tab. 3, fig. ';, 

 ArgyropelecM Olfcrsii, Cuvier and Valbncienne.s, xxii, 408. — Lowe, Proc. Zool. Soc, 1850, 247. — Gunther, 



Cat. Fisli. Brit. Mus., v, 380.— \'aillant, Exi>. Sci. Travailleur et Talisman, 104. 



Height of the body is equal to, or rather less than, distance between the shoulder and 

 the root of the caudal fin, tail at its base, below the end of the dorsal fin, as high as long. 

 Mandible with a short, flat spin:- at its po.sterior corner; angle of the preoperculuni w ith a 

 spine directed downwards; tail witliout spines. Pectoral fin extends to ventral, {(liinthcr.) 



Radial formula: B. 9; D. 9; A. 11; P. 10; V. 6. 



This s])ecies, like the others just described, has hitherto been considered to be a pelagic, 

 surface form, and has now and then been found as far north as the coast of Norway, and was 

 taken by the Frencih expedition off Portugal in O.jO and 1,015 meters. The Challenger dredged 

 a specimen 2^ inclies long, at a depth of 1,125 fathoms, at Station i, off Cape FinisteiTe. 



Dr. Giinther, discussing this occurrence, remarks: "The question arises whether the 

 fish was really captured at this great dejith, or whether it entered the dredge diu-ing its 



