FAUNE DU CALCAIRE CARBONIFERE DE LA BELGIQUE. 
25 
of the upper lobe of the tail. About 50 rays may be counted in it, rapidly increasing in length to 
tbe 10"', wbich is the longest. The length of the base of the dorsal fin is 2 inches; of its longest 
rays 1 ’/ 2 . Tbe anal fin commences at a distance of 6 % inches beliind tîie tip of the snout; in 
form it also ressemble tbe anal of Eurynotus, being triangular and acuminate, with short base of 
origin. Tbe length of its base is 1 J / 2 inch, which is the same as tbat of its longest rays; 
the number of rays unfortunately cannot be counted. The caudal is powerfully heterocercal and 
apparently deeply cleft, though it is not in very good préservation, the rays of the upper lobe being 
almost entirely gone, and those of the Iower not preserved up to their extremities. The rays of tbose 
médian fins are tolerably coarse, and divided by transverse articulations, which are distant enough 
to make the joints appear about twice as long as broad; conspicuous fulcra are seen on the anterior 
margins of at least the dorsal, and Iower lobe of the caudal. 
Remarks. — The form ofthe dorsal fin, and more especially the structure of the head render it 
évident that the above described fisli, to which I hâve givcn the generic name Bencdenius in 
lionour of its first descri ber, the distinguished Professor of zoologie in Louvain, cannot be included 
in the familv Palæoniscidæ, but that, on the other hand, it must take ils place with those Hetero¬ 
cercal Ganoids whose affinities point more or less in the direction of Platysomus. And among these 
forms, which may be appropriately classcd together as Platysomidæ, there seems to me to be 
little doubt that Eurynotus is the one to which the subject of the présent description is mosl closely 
allied. It is true that, most unfortunately, the dentition of the two généra cannot be compared. But 
in the general shape of the body and head, in the form of the dorsal and anal fins, and of the 
powerfully heterocercal tail, the resemblances of Benedenius to Eurynotus are obvions. Equally 
obvious are also tbe distinctions between them, as seen in tbe smaller size and shorter base ofthe 
dorsal fin, and its much more posterior commencement; the delicacy of the pectoral fins, which in 
Eurynotus are very large and powerful and the seules or large scales of the dorsal and ventral 
margins of the body, which form indeed a mos! peculiar feature of the genus. 
\\ 
Geological Position and Locality. — Discovered by Al. de Montpellier d’Annevoie in the carbo- 
niferous limestone of Denée in Belgium and presenled by him to the Muséum at Louvain. 
Ramsay H. Traquair. M. D. 
Keeper of the natural history collections in the Muséum of Science, and Art at Edmburgh. 
