ENCHELYOLEPIS. 81 



Description of Specimen. — The type specimen, discovered by the Rev. W. H. 

 Andrews, is shown somewhat enlarged in PI. XVII, fig. 6, and is preserved in 

 counterpart. The remains of the head are merely sufficient to show that it is 

 shaped as in the Macrosemiidas, with a comparatively small terminal mouth and a 

 close series of styliform teeth in both jaws. There are apparently pro-otic and 

 opisthotic ossifications in the lateral Avail of the brain-case. An epihyal and ;i 

 relatively large ceratohyal bear a feAV branchiostegal rays, of which four are 

 slender and much curved. In the vertebral axis there are about 35 segments, of 

 which 14 may be reckoned as abdominal. Centra seem to be represented by 

 delicate complete cylinders in the abdominal region, but by not more than small 

 pleurocentra and hypocentra in the caudal region — a condition possibly due to 

 the immaturity of the specimen. In Enchelyolepis pectoralis, however, complete 

 vertebral rings are seen throughout the axis (PI. XVII, fig. 7). The ribs are 

 comparatively slender, and are far from reaching the ventral border of the fish. 

 The neural arches generally, and the haemal arches in the caudal region, are very 

 short and stout and much inclined to overlap. A few of the anterior neural arches 

 are expanded at the upper end, which is seen. to be forked in E. pectoralis ; about 

 four of the neural arches at the base of the caudal fin are longer than the others 

 and very closely arranged. Eight or nine elongated hgemals are supports of the 

 caudal fin. The stout clavicle is considerably expanded above the pectoral fin, 

 which is inserted close to the ventral border of the fish, but is only fragmentary in 

 the fossil. In E. pectoralis the pectoral fin consists of about 12 articulated rays 

 supported by 4 well -calcified basals which rapidly decrease in size from below 

 upwards. Each pelvic fin-support is characterised by its relatively large and wide 

 proximal triangular expansion ; while between this support and the 5 or 6 pelvic 

 fin-rays in E. pectoralis there seem to be small nodular baseosts. The dorsal fin 

 seems to have been equally elevated throughout its length, and some of the rays 

 clearly show their distal bifurcation. All its 25 supports (fig. 6 a) are especially 

 stout, larger than the neural spines, and sharply curved forwards at their pointed 

 lower end. Between each of these supports and its corresponding ray is inter- 

 calated a very short bony rod, as in Amia^ — an arrangement seen again in 

 Enchelyolepis pectoralis, where there is also another small nodule of bone between 

 the short rod and the fin-ray (fig. 7 a). The anal fin, with its 7 rays, exhibits 

 similar stout supports. Of the caudal fin only the base is preserved ; but in 

 E. pectoralis it is nearly complete and shows the rounded or truncated posterior 

 border. Traces of scales are vaguely seen over nearly the whole of the trunk in 

 the fossil, but they must have been extremely thin. They appear to be at least as 

 long as deep and much overlapping, the large covered portion being marked only 

 by the usual concentric lines of growth, while the small exposed portion, which is 

 rounded at the hinder border, has a regular reticulate structure (PI. XVII, fig. 6 b). 

 1 T. W. Bridge, iu ' The Cambridge Natural History,' vol. vii (1904), p. 235, fig. 136. 



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