26 



BRITISH FOSSILS. 



The Genus HOL OPHA G US, Egerton. 



The unique specimen upon which this genus is based is thus 

 described by Sir Philip Egerton in a note at page 1 9 of the " Pre- 

 liminary Essay " of the tenth Decade : — 



Holophagus Gulo. 



" Mr. Harrison's specimen wants the anterior portion from the dorsal 

 and pectoral fins forwards. From the insertion of the dorsal fin to the 

 extremity of the tail it measures 11^ inches, and 4J inches in depth. 

 The stomach is distended with a recently swallowed Dapedius, and a 

 large coprolite occupies the rectum. The first dorsal fin springs (as in 

 Macropomd) from a single disc, resulting from the coalescence of the 

 interneural spines. It contains eight long, thick, undivided, and multi- 

 articulate rays. They are beset with numerous short spines or tuber- 

 cles. The second dorsal is situated 4 inches behind the first. Between 

 the two is seen a strong bifurcate interneural ossicle, which has been 

 displaced forwards from its proper position at the base of the fin. The 

 second dorsal fin contains sixteen rays. The anterior ones are short 

 and slender. The succeeding ones are long, broad, and multiarticulate, 

 but not tuberculate. The base of the fin is obtusely lobate, with a scaly 

 investment. The pectoral fins are much mutilated. Judging from 

 what remains of them, and from some indistinct impressions, they seem 

 to have been of great size. The anal fin occurs immediately below the 

 second dorsal fin, with which it con'esponds in form and structure, but 

 contains many more rays. The ventral fins are mutilated, but their 

 position below the first dorsal fin is indicated by the preservation of a 

 pair of strong T-shaped pelvic bones, having their longer limbs directed 

 forwards, and nearly reaching the base of the pectoral fins. The 

 caudal fin is of great size, and presents in an eminent degree the most 

 special and characteristic feature of the Coelacanthus family, namely, 

 the interposition, in the caudal region, of an interneural between the 

 neural and dermoneural spines. The base of this spine abuts upon the 

 extremity of the neural spine, and unites with the true fin ray by an 

 overlap or splice. This structure coincides with that observed in Un- 

 dina. In Macropoma the bone of the interneural spine is bifurcate 

 for the reception of the distal extremity of the neurapophysis. A small 

 supplemental fin extends an inch beyond the larger caudal fin, as in 

 Undina and Ccdacantlius. The notochord is unossified. The apo- 

 physes, both above and below, have very wide bases. The scales are 

 eurvihnear, and covered with a vermiculate pattern on the upper sur- 

 face, occasionally broken up into small tubercles." 



The specimen referred to in the foregoing description is in the 

 Museum of Practical Geology, and is figured, one-half the size of 

 nature^ in Plate YI. ; with enlarged views of a scale, of anal and or 

 caudal fin-rays. D is the first dorsal fin ; Z)^, the second dorsal 

 fin; Z)U, its interspinous bone; A, the anal fin; (7, the 

 caudal fin ; the supplemental caudal fin-rays ; Pv^ the pelvic 

 bones. 



