912 



SCANDINAVIAN FISHES. 



Gexis ARGENTINA'. 



Jaws tootlih'ss, but the pfilnfe armed In front ivith a semicircitlar transverse roic of small hut pointed, recurred 

 teeth, and the tongue furnished within its fleshy rim with a similar, hut sparser roiv of somewhat larger teeth. 

 Length of the maxillaries at most about SO % {26 — 29^ j., %) of that of the head reduced, and the length of the 

 lower jaw at most ahout '>() % (4-'l — 4!)\ ., ?i) of the same. lireadth of the snout at the articular knohs of the 

 maxillaries percejdihlg less than that of the interorhital space, u'hich is more than ' ^ {2(> — 2!) %) of the length 

 of the head. Base of the dorscd fin less than 8 % of the length of the hodi/^, or than half the length of the 

 head reduced. Fyloric appendages little or moderately developed. Scales large, for the most part curved., and 

 armed with small spines. Ahout GO (.56') — 70 scales in the lateral line, rvhich is complete, and the scales of 

 which are rendered more or less heart-shaped hy an indentation at the hind margin. 



In the genus Argcntinii we find reminiscences both 

 of the Smelts and tlie following f;imily: ;i certiiin de- 

 gree of transijarency niid cucutnhcr-like smell (not 

 quite absent, however, in the Gwyiiiads) and a com- 

 paratively smair number of pyloric appendages point 

 to the former; the stiff, but fragile tin-rays and the 

 singular shape of the scales remind us of the latter. 

 The last-mentioned peculiarity, which is also connected 

 with the formation of the longitudinal ridges that 

 appear on the sides of the body in Argentina, and are 

 each covered by a row of curved scales indented at the 

 hind margin (similar in this respect to those of the 

 lateral line), ranges Argentina beside the extinct genus 

 Osmeroides of tlie (Jretaceous Period'', though in other 

 respects the latter genus, with its numerous branchio- 

 stegal rays and its strong, toothed jaw-bones, was 

 more like the Salmons. In Argentina the jaws are 

 comparatively weak, and there are no jaw-teeth, while 

 the maxillaries are without supplementary (jugal) bones. 

 I5ut tlie most striking among the other characteristics 

 of Argentina is the reduction of the rostral region 

 proper, which both in the Salmons and the Gwyniads 

 is sometimes so considerably elongated. Here, on the 

 other hand, the ethmoidal region, with its lower covei'- 

 ing-bone, the vomer, is well-developed and compara- 

 tively long; but the intermaxillaries are so greatly 

 reduced that the head of the vomer, in almost the 



same manner as in the 1'a'Is, seems to form the tiriii 

 anterior mai'gin of the mouth. Lastly we will mention 

 a characteristic which is indeed not quite absent in the 

 Gwyniads, but is there mtich less developed, almost 

 rudimentary. Outside (under) the pelvic bones and in 

 front of the insertions of the pectox'al tins, the large 

 ventral scales form a flap, free behind, whicii covers a 

 great pai't of the ventral tins when they are folded. 



Argentina belongs to the deep-sea fishes — as the 

 large eyes indicate — but not to their most character- 

 istic types. The young are fretpiently met with in the 

 upper marine zones, and even ascend, according to 

 NiLssox', to the mouths of rivers. In the depths of 

 the ocean the genus probably has an extensive range. 

 It has longest been known, for a long time exclusively, 

 fi-om the North Atlantic and the Mediterranean; but 

 in 1878 it was found oft" the coast of New Zealand, and 

 this in a form that can hardly be distinguished from 

 one of the Atlantic species. Such a find as this most 

 naturalh' suggests the possibility of discovering the spe- 

 cies in intermediate localities as well; but it is remark- 

 able that New Zealand is also the only region in the 

 Southern Hemisphere which possesses among its auto- 

 chthonic fresli-water fishes a member of the Salmon fa- 

 mily {Retropinna Bichardsonii). 



( >nly two species of the genus Argentina are 

 known with certainty'^. 



" Artedi, Ichlhyril., Gen. Pise, p. 8. 



' In a damaged specimen Brown-Goode and Bean found the length of tlie base of the dorsal fin to be 8'4 % of tliat of the body. 



' According to Nilsson, however, sometimes 20. 



'' Agassiz, Rech. Poiss. Foss., tome V, II"ie Partie, p, 105, PI. 00 b. 



' Observationes Ichihyologica:, p. 7; iShand. Fna, Fisk., p. 470. 



•' Valenciennes' Anjentina leiocjlosf^a (without teeth on the tongue) from the Mediterranean oif Algiers has already been identified by 

 GiGLiOLi with A. sphiira>.na, and IIutton's Argentina elongata from New Zealand is based on a single young specimen in bad condition (see 

 GtJNTHER, Deep Sea Fishes, Chall. Exped., p. 218). 



