204 



SCANDINAVIAN FISHES. 



of tlie earlier (lower) stages of tlevelopmeut. It also 

 seems probable that the p;ilatine and vomerine teeth 

 are subject to similar clianges and disappear with 

 increasing age, for traces of teeth (small and to be 

 distinguished only by the touch) occur, in exceptional 

 cases, on the vomer in Anonns decagonus. We have, 

 liowover, no further observations on this point. 



The family belongs chiefly to the depths of the 

 Arctic seas — one genus, hinvever, Jfjoinqisi'^, with 



two dorsal tins ;nid both vomerine and p;ilatine teeth, 

 belon<TS to the Antarctic fauna. The true haunt of 

 these fishes is ;ip}>arently the soft, clayey bottom, where 

 they feed on all kinds of small animals and often fall 

 a prey to the Halibut, being subsequently found in its 

 stomach. Some S])ecies, however, ascend nearer the 

 surface. Jordan and Gilbert estimate the numl)er of 

 species at about 16. In the Scaiidinnvian fauna only 



Genus AGONUS. 



Tiro (Jnrsal fins. 



Falatinc hones ami roiiier toothless. Tip of the snout projeeting in front of the loirer juir. 

 Caudal region elongated and loiv. 



Thus defined", the genus Agon us, which was esta- 

 blished I)y BLOCH^ includes Gill's genus Podothecus". 

 According to this opinion four species are known, t\vo 

 of which l)elong to the northern ])arts of the l)asin of 

 the Atlantic and two live in the corresponding parts 

 of the Pacific. The first two may be most easily dis- 

 tinguished by the different numl)or of pairs of plates 



(posteriorly forming onl}' one row) from the occiput to 

 the caudal fin: 



A : Xvimber of paired and impaired pla- 

 tes in a row on the back from the 

 occiput to the caudal fin above 40... Agomis decagonus. 



B: Number of paired and unpaired pla- 

 tes in a row on the back from the 

 occiput to the caudal Tin under 37... Agonus ratcphractim. 



" Cf. Steindachner. Stzber. AktiJ. Wiss. Wien, LXXXII (1880), I, \>. 255. 



'> Blochii Syst. Ic/ithi/oL, cd. Schn., p. 10-i. One year later (1802) L.\cepepe (ITist. yat. Pois.^., tome III, p. 221) en(itlef) (his 

 genus Aspidoplionis. 



' Proc. Acad. Nat. Sc. riiilail. ISHl, p. 259. 



