Pernio- Carboniferous Fishes from Madagascar. 3 



(fig. 1, n.) ; but it can only be stated that they are stout rods. 

 As shown by a vague impression in nearly all specimens 

 (e. g. fig. 1, x), the abdominal cavity is bordered behind by a 

 large curved bone, which extends downwards and forwards 

 from the vertebral axis to the origin of the anal fin. This is 

 of uncertain nature, but evidently corresponds with a bone 

 which is always conspicuous in the naked Permian Platy- 

 somid, Donjpferus *. 



In the pectoral arch the clavicle is relatively large, and 

 ends below in a convex expansion (fig. 2, cL). This ex- 

 pansion and all the exposed plates of the arch are closely 

 ornamented, like the head-bones, with more or less nearly 

 vertical and wavy striations* The pectoral fin (figs. 2, 3, pet.) 

 is inserted just above the expansion, on the flank, and its 

 longest rays extend across about 12 vertical rows of flank- 

 scales. It consists of not less than 25 rays, supported by 7 

 or 8 elongated, hourglass-shaped basals (/>.), which are only 

 superficially calcified. The foremost rays rapidly lengthen 

 in succession at the front or upper border of the fin, and the 

 longest rays are within its anterior or Upper half. All are 

 crossed by distant articulations, and all except the foremost 

 lengthening rays are finely subdivided distally. The fin 

 bears no fulcra. There are no traces of pelvic fins even in 

 well-preserved specimens. The dorsal and anal fins are 

 remarkably extended, the anal arising at the hinder end of 

 the abdominal cavity and terminating on the contracted 

 caudal pedicle, while the dorsal arises even slightly further 

 forwards with the same hinder termination. Each fin is 

 borne by stout endoskeletal supports much less numerous 

 than the dermal rays ; and those of the dorsal fin are clearly 

 shown in the usual double series (fig. 4, bo., ao„). The two 

 fins are similar in shape, the foremost rays being crowded, 

 rapidly increasing in length at the anterior border to a low peak, 

 and then more gradually shortening again until the hinder 

 half of the fin is low and fringe-like, with less crowded and 

 finer rays. All the rays are crossed by distant articulations, 

 and those of the stout front portion (fig. 3 b) are ornamented 

 with oblique and partially longitudinal strise, which are fewer 

 and coarser than the striae of the scale-ornament. Of the 

 caudal fin, only the base is observable in the type-specimen 

 (fig. 1, c). The upper caudal lobe bears large ridge-scales, 

 while the slender fin-rays are crowded and crossed by distant 

 articulations. There are no fulcra on the median fins. 



* A. Hancock and R. Howse, " On Dorypterus hoffmanni, Gerniar, 

 from the Marl Slate of Midderidge, Durham," Quart, Journ. Geol. Soc. 

 vol. xxvi. (1870), p. 632. 



1* 



