RHADINTCHTHYS ORNATISSIMUS. 



129 



parallel with the superior and inferior margins. In the furrows between these ridges 

 numerous punctures may be observed, and often about the eentre of the scale the ridges 

 are over a small space nearly obsolete, so that the punctures come more prominently 

 into view, and the ridges themselves end in fine denticulations of the hinder margin. 

 Fig. represents a scale taken from further back, in which the ridges are fewer and 

 more oblique, passing, however, anteriorly into very fine striae, while in fig. 7 we have 

 another posterior scale in which the coarser ridges have disappeared, and their place is 

 altogether taken by fine oblique striae. 



The paired fins are rather small, the pectoral attaining only about one-half the length 

 of the head. It is well shown in the specimen represented in Fl. XXVIII, fig. 2, and 

 consists of about thirty rays, of which the principal ones are, as in Pygopterus and 

 Oxygnathm, unarticulated till towards their terminations. The ventral is placed nearer 

 to the anal than to the pectoral. The dorsal and anal fins are moderate, the former 



Fig. 6. — Restored outline of Rhadinichllnis oruatisshnux (Agassiz). o., orbit; op., operculum; p.op., preoper- 

 culum ; «. 0/)., suboperculuin ; &*•,, brauchiostegal plates ; hjj;., uiaxilla ; )««., niiiiuliblc ; ri., clavicle ; s.cZ., supra- 

 clavicular ; pt. t., post-temporal. The fiu-fukra have beeu omitted, being too minute for a drawing on so small 

 a scale. 



being placed far back and arising oidy slightly in front of the anal ; both are acuminate, 

 triangular, with concave posterior margins. It is not possible to ascertain the number 

 of rays in these fins. They are rather delicate, and having their transverse joints about 

 twice as long as broad — at least in the longer rays before bifurcation — when the rays 

 are in situ their articulations appear proportionately still more distant (fig. 8) owing to 

 the imbrication of the demi-rays. The tail-jjedicle is rather long ; the caudal body- 

 prolongation is weak, and the lower lobe of the caudal fin is largely developed. The 

 anterior rays of this lower lobe are stouter than those of the rest of the fin and have 

 their transverse articulations closer, the joints appearing nearly square as seen from the 

 outside ; as the lower lobe passes into the upper one the rays become more delicate and 

 their articulations more distant. The outer surfaces of the joints of these fins are mostly 

 smooth, though showing here and there traces of longitudinal striation (see fig. 8), 

 especially towards their proximal extremities. The fulcra are small, though very 

 distinctly visible under an ordinary lens. 



