102 WEALDEN AND PURBECK FOSSIL FISHES. 



Remarks. — Representatives both of the pectinate-scaled and of the smooth-scaled 

 forms of Pholidophorus occur in the Purbeck Beds. They are remarkable for the 

 stoutness of the fulcra on the tins. 



1. Pholidophorus ornatus, Agassiz. Plate XX, figs. 5 — 8; Piatt- XXI, fig. I ; 



Text- figure 34. 



1843-44. Pholidophorus ornatus, L. Agassiz, Poiss. Foss., vol. ii, pt. i, p. 280, pi. xxxvii, figs. 6, 7. 

 1855. Pholidophorus ornatus, P. M. (x. Egerton, Figs, and Descripts. Brit. Organic Remains (Mem. 



Geol. Surv.), dec. viii, no. 4, p. 1, pi. iv, fig. 3. 

 1895. Pholidophorus ornatus, A. S. Woodward, Catal. Foss. Fishes, Brit. Mns., pt. iii. j>. 471. 



Type. — Imperfect tail ; British Museum. 



Specific Characters.- — Attaining a length of about 20 cm. Length of head with 

 opercular apparatus nearly equal to the maximum depth of the trunk and occupying 

 between one-quarter and one-fifth of the total length of the fish. Head and 

 opercular bones very feebly rugose or smooth; maxilla not much arched; teeth 

 obtusely pointed. Fin-rays smooth and stout, and fulcra comparatively large. 

 Pelvic fins arising midway between the pectoral and anal fins, and opposed to the 

 dorsal fin, of which the length of the longest ray about equals the depth of the trunk 

 at its insertion. Scales ornamented with coarse oblique pectinations ending in sharp 

 serrations ; about six flank-scales in each abdominal transverse series deeper than 

 broad ; lateral line marked by notches on the scales in the abdominal region, 

 forming a sharp smooth ridge on the scales in the hinder part of the caudal region. 



Description of Specimens. — The type specimen in the Man tell Collection 

 (PI. XX, fig. 5) exhibits only the imperfect caudal region, and is very unsatisfactorily 

 described and figured by Agassiz, Inc. eit. The thin cylindrical vertebral centra 

 (v.) are seen, though crushed, near the base of the caudal fin, while the comparatively 

 short and stout neural and haemal arches are shown to be sharply inclined backwards 

 and thus deeply overlapping. A fragment of the pelvic fin (plv.) proves that it 

 was rather large. The small anal fin (a.) bears a close series of short and slender 

 fulcra, The dorsal fin is absent, though false appearances of it were misinterpreted 

 and described by Agassiz. The stout rays of the forked caudal fin are enamelled, 

 and with rather distant articulations. Its fringing fulcra are small and in very close 

 series. The scales exhibit the characteristic pectination of the posterior border even 

 to the base of the caudal fin ; and there is one enlarged, elongated dorsal ridge- 

 scale, with faint rugose ornament, at the origin of the upper caudal lobe. Traces 

 of a smooth longitudinal keel are seen on some of the scales of the lateral line. 



Other specimens now exhibit nearly all the principal characters of the genus 

 and species, and one small fish (PL XX, fig. 0), discovered by Mr. Alexander J. 

 Hogg, is especially fine, only crushed and incomplete towards the end of the tail. 



