<J1 IIISTIONOTUS ANGULARIS. 



its head. Sir Philip Egerton, misled by the imperfect preservation 

 of the posterior end of his specimen, thought the caudal fin to be 

 similar to that of Lepidotus. By a singular coincidence a fine 

 specimen of Lepidotus minor lies side by side on the same slab with 

 the subject of this note, and the caudal fin of each is well exposed, 

 showing that of Lepidotus to be comparatively short and truncate, 

 while that of Histionotus is deeply forked. In its crushed condition 

 the upper lobe in Histionotus is longer and larger than the lower 

 lobe ; but this is proved to be a deceptive appearance by another 

 example of the genus I have since met with from the same quarry, 

 which displays the symmetry of the tail fin, the lobes being 

 beautifully shown of equal length. 



The outline of the upper portion of the body is triangular, rising 

 abruptly from the snout to a distance of 20 millim. beyond the base 

 of the occiput along the dorsal ridge, and then descending by a less 

 abrupt gradient from this culminating point to the base of the 

 caudal fin, a distance of 85 millim. The depth of the body at the 

 most elevated part of the dorsal ridge to the pectoral fin is 65 mm., 

 to the shoulder-girdle 33 mm. 



The anterior margin of the first ray of the dorsal fin, which 

 is stouter than the others, is furnished with a series of fulcral 

 rays. The remaining rays, of which there are more than 20, 

 bifurcate about half-way from the base, and the distal halves 

 are again bifurcated and cleft. The pectoral fin consists of seven 

 rays, of which the first is the longest and stoutest, all are 

 bifurcate and split. Each ventral fin, which is 20 mm. long, has 

 only four rays, the first exceedingly stout and furnished with a 

 series of large marginal fulcra ; and all the rays are transversely 

 articulated, or jointed, beyond the point of bifurcation. The anal 

 fin has four rays also, and is the smallest of all ; the length of the 

 largest ray being 15 mm. The caudal fin consists of eight rays in 

 each lobe, the upper lobe appearing 40 mm. long, whereas the lower 

 is only 25 mm. The margins of the upper ray of the larger lobe, and 

 of the lower ray of the smaller, are furnished with a series of large 

 fulcra, which probably increased the locomotive power of the tail. 



