XVI. Ona new Sub-genus of Fishes, allied to Ophidium. By Wit.i1am Tuompson, Esq., 
Vice-President of the Natural History Society of Belfast. Communicated by the Se- 
cretary. 
Read June 13th, 1837. 
THE species of fish which is the subject of the present communication ranks under 
the Malacopterygii Apodes, and in its genus most nearly approximates Ophidium. 
Although with Ophidium, as described in the “ Reégne Animal” (t. 2. p- 358. 2nd ed.), 
it possesses many characters in common, others are at the same time presented which 
have suggested the propriety of constituting it a sub-genus. Cuvier having given 
as a character of Ophidium, “‘Vanus assez en arriére,” strictly considered’ prevents 
the admission of the present specimen. The genus is, again, in the Régne Animal 
subdivided into the true Ophidia and the Fierasfers; the former, ‘ Portent sous la 
gorge deux paires de petits barbillons adhérents 4 la pointe de d’os hyoide,” and the 
latter, ‘‘ Manquent de barbillons, et leur dorsale est si mince, qu'elle ne semble qu’un 
léger repli de la peau.” 
In external characters—for the specimen being, so far as known to me, unique, I have 
been unwilling to injure its appearance by dissection,—it is excluded from the Ophidia 
proper in consequence of not having the barbules ; and though agreeing with the Fieras- 
fers in the negative character of wanting these appendages, yet, by having the dorsal 
fin strongly developed and elevated, it ranges not with them. 
Its want of the very obvious character of the Ophidia, renders all comparison with 
them unnecessary ; but of two species belonging to the Fierasfers, and which approach 
the present specimen most nearly, I may state, that it possesses many of the characters 
of the Oph. fierasfer of Risso, but differs from that species in the teeth, (both jaws 
are described as armed with three rows of sharp and hooked teeth,) number of fin- 
rays, and some minor characters ; besides, there is nothing said of the remarkable 
teeth terminating both jaws, as exhibited in my specimen. In the Régne Animal we 
again find an Oph. dentatum described as having in each jaw “ deux dents en crochets,” 
but no further details are given. In this only character, however, the Oph. dentatum 
' It may, perhaps, be objected to this strict reading, that Cuvier has himself admitted into the genus the 
Oph. Vassalii, which is described by Risso as having “I’anus situé prés de la gorge”’ (tome iii. p. 212. ed. 1826); 
but although the characters of this species are pretty fully detailed in the Régne Animal (t. ii. p. 359.), the one 
here quoted from Risso is not mentioned. The last-named author similarly describes the position of the vent 
in the Oph. fierasfer. On the contrary, both of the British Ophidia figured by Pennant (Brit. Zool. vol. iy. pl. 93. 
ed. 1777), and Montagu (Wern. Mem. vol. i. pl. 4.), accord with Cuvier’s generic description in this cha- 
racter, 
