66 GANOID FISHES OF THE CARBONIFEROUS FORMATION. 



a length of five or six inches, and is distinguished from the immature specimens solely 

 by the greater closeness of the transverse articulations of the fin-rays. 



FygojAerus Bucldandi of Agassiz {Elonickthys Bucklandi, Traq.) is probably, as sug- 

 gested by Smith Woodward, the extreme adult form of the typical E. Robisoni as it 

 occurs in the same beds at Burdiehouse and Burntisland, as it is not only difficult con- 

 cisely to define it as a species, but also to assign to it a special immature form of its own. 

 Agassiz's brief statement regarding it in the ' Poissons Fossiles ' is as follows : — " Espece 

 characterisee par la petitesse et la forme allongee de ses ecailles, et par son anale tres 

 rapprochee de la caudale. Elle est a-peu-pres de la taille du Pygopterus mandibularis, et 

 provient du calcaire de Burdiehouse en Ecosse. L'originale se trouve dans la collection 

 de la Societe Royale d'Edinbourg." 



The specimen to which these words refer was figured by Hibbert in his Burdiehouse 

 Memoir (pi. vii, fig. 2), but seems unfortunately to be lost, as, many years ago, I 

 sought for it in vain in the collection of the Royal Society of Edinburgh. But there can 

 be no doubt as to what manner of fish it was, as the figure enabled me confidently to 

 refer to it a number of mostly fragmentary remains of a large Elonickthys from Burdie- 

 house contained in the Edinburgh Museum of Science and Art. These s[)ecimens repre- 

 sent a fish which seems to have attained the length of a foot or more, having the trans- 

 verse articulations of the fin-rays close, and the scales proportionately small. 'Y\\<i latter 

 are, on the flank, nearly equilateral, but towards the ventral margin they are low and 

 narrow. The anterior covered area is very narrow ; the posterior margin is finely den- 

 ticulated. The exposed area is covered with a delicate yet sharply defined ornamenta- 

 tion, consistiiig of fine subparallel ridges, which pass from before backwards across the 

 scale in a gently sigmoid direction, tending to become intermixed with punctures 

 posteriorly, especially above the diagonal between the two acute angles of the scale. 

 Towards the tail the ridges become less marked on the posterior part of the scale, giving 

 way to the thickly dotted punctures, till on the caudal body prolongation the former, 

 after lingering at the anterior margin, altogether disappeai-, and punctures alone reujain. 

 A certain amount of reticulation is also frequently oi)served as regards the ridges. 



The characters on which I previously depended for maintaining this form as a separate 

 species are, therefore, the proportional small size of the scales, their highly ornate, clear- 

 cut sculpture, and the extra closeness of the transverse articulations of the fin-rays, but 

 long experience has now taught me that in this group of forms these marks are subject 

 to endless gradations, and are consequently not reliable as specific distinctions. Elonichthys 

 Bucklandi must therefore be relegated to the list of synonyms of E. Robisoni. 



In PI. XIV, figs. 4 — 8, the ordinary sculpture of the scales of this form, as 

 seen in Burdiehouse specimens, is represented magnified eight times ; the articular peg 

 is, however, omitted, being covered in each case by the scale next above. Fig. 5 is a 

 lateral-line scale from the flank ; figs. 6 — 8 are narrow scales from a position close above 

 the base of the anal fin. 



