270 



SCANDINAVIAN FISHES. 



Nat., torn. IX (1874), p. 310: Coll. (Lutninculodes), Forh. 

 Vid. Selsk. Clirist. 1874, p. 151; ibid., Tilla>gsh., p. 60; 

 In. iCnjstallogobius). ibid. 1876, No. 6, p. 26, tab. II, fig. 

 — 14: Mai>m, GImjs, Boh. Fn., p. 651; Coli... 1. c. 1879, 

 No. 1, p. 36; Day, FL^h. G:t Brit., Irel,, vol. I, p. 172, 

 tab. LIII, fig. 4: LiLU., Sv., Norg. Fisk., vol. I, p. 640; 

 Coll., N. Mag. Naturv., Cbrist,, Bd. 20 (1884), p. 63. 



('r!id((Uof)ohim Nilssonii, is essentially of the same 

 tofiii as the pi'eceding species, and of eiiiial or even 

 greater transpai-ency. The body is, however, still more 

 strongly compressed; and the great length of the second 

 dorsal and the anal tins, the shoi'tness of the first dorsal 

 fin, and the arcuate, upturned form of the loAver jaw, 

 Avith the peculiar structure of the teeth in the male 

 (tig. 72, r/ and e), condjiuc to give this species an en- 

 tireh' different appearance. Another remarkable point 

 in this tish is tiie broad (nuiltiradiate), somewhat lobate 

 form of the pectoral fins, with their semicircular, mus- 

 cular root and elongated, roundish shape, furnished as 

 they are with short, tine rays at the top and bottom, 

 and with the middle 12 — 14 rays longest, though much 

 shorter than in the preceding species, and even in the 

 males only about 10 % of the length of the body." When 

 expanded, the pectoral fins ai-e as deep as the body. The 

 development of the fins in this species is, however, 

 widely different in the dift'erent sexes. The second ray 

 in tlie first dorsal fin is the longer, and the fin-mem- 

 l)rane sometimes extends back to the beginning of the 

 second dorsal fin, l)ut is generally nuich shorter. In 

 the females (fig. 72. c) this fin is remarkably low, 

 being often scarcely distinguishable, Avhich is also the 

 case with the ventral fins, while the second dorsal and 

 anal fins are also lower in tlie female than in the 

 male, and the pectoral fins much shorter. According 

 to V. DuBEN and Koren's measurements of specimens 

 from 31 to 42 mm. long, the fins also undergo con- 

 siderable changes of growth, the base of the second 

 dorsal fin increasing from 30 to 35 % of the length of 

 the bod)', the base of the anal fin, on the other hand, 

 being reduced from 36 to 35 % thereof, while the dis- 

 tance between the tip of the lower jaw and the vent 

 is reduced from 45 to 42 % of the length of the body, 

 and the distance between the first dorsal fin and the 

 tip of the snout from 23 to 22 %. According to the 

 same measurements tlie greatest depth of tlie body 

 sinks from 13 to 11 % of the length, and the least 

 depth from 8 to 7 %. Again, according to the same 



measurements, the length of the head is about 17 % 

 of that of the liod)-; l)ut in two females, 33 and 38 

 mm. long, sent us from C'hristiania Fjord, by Pro- 

 fessor CoLLiCTT, this ratio varies between 15 and 16 %, 

 and in Uvo males from the same place, 44 and 45 mm. 

 long, it is 20 %. Tiie longitudinal diameter of the 

 e^'e decreases, according to v. DCben and Koren, from 

 29 to 23'/ 2 % of the length of the head. In our own 

 specimens the length of the lower jaw varies between 

 56' 2 and 60 % of that of the head. 



To the best of our knowledge Cri/stallof/obuis AvV.s- 

 sonii has only twice been found in Sweden, on both 

 occasions near the entrance of Gullmar Fjord. In July, 

 1877, oft" Gaso, Malm found a male and a female which 

 had probably been drawn up in a net from a depth of 

 14 fathoms; and among the collections whieii Dr. Wi- 

 REN brought with him in 18S5 from the Zoological 

 Station of Christineberg, was a male specimen 36 mm. 

 in length. ( )n the Norwegian coast, on the other hand, 

 it has repeatedly been met with, in some years in 

 fairly lai'ge numbers, though at other times, like the 

 preceding species, it .seems to l)e extremelv rare. The 

 first specimens, 5 in luimber, were taken by Stuvitz 

 oft" Steen, near Bergen, in December, 1834. Off Aske- 

 AN'old, in the north of the Department of Bergen, Go- 

 vernoi' ('hristie took two specimens, wdiich were 

 also placed at v. DOben and Koren's disposal in tlie 

 Museum of Bergen. These writers also mention two 

 other specimens which they had personally taken in a 

 dredge, at a depth of about 30 fathoms, oft' Christi- 

 anssund, in July. 1843. Each of tliese specimens was 

 found hidden in the emptA' shell of a worm (GJuc- 

 fopferits 'iiorvcgicifs). Both of the Norwegian zoologists 

 Sars have subsequently met with this species at several 

 Sjwts in the south of Norway; and in recent years, 

 from 1875 to the present time, it has repeatedly been 

 found by Collett during the seine-fishery for Macke- 

 rel, Sprats and Cod in Christiania Fjord. In June, 

 1879, in particular, he took about a hundred specimens 

 among a small shoal of Herrings that was netted in 

 Sandvig, some Swedish miles south-west of Christiania. 

 June is approximately the spawning-season of this 

 species; and its habits are in all probability much like 

 those of Aphija mim(f((, in companj" with which it is 

 often found. Like the latter species it is also com- 

 prised among the fishes called Aaf by the Norwegians, 



" In tbis respect Collktt's figure is less accurnte tlian v. Dl'nEN and Koren's and Pay'.s figures above referred to. 



