THE CCELACANTHINI. 



15 



than the head ; size small, not exceeding 4 to 5 inches in length ; 

 upper surface of head ornamented with tubercles, which are much 

 larger and more remote than in preceding species ; opercula and 

 maxillaries threaded, and like the scales, having stronger markings 

 than in the larger species. 



" Radial formula, A.D. 8 ; P.D. 5 ; C. 24 ? ; A. 6 ; V. ? ; P. ?. 



" C. elegans, Newb. Body fusiform, robust, 6 to 8 inches in 

 length ; cranial surface covered with closely-approximated tubercles; 

 surface of opercular and maxillary bones threaded. All the orna- 

 menting of the head relatively stronger than in C. robustus, but 

 less so than in C. ornatus. Scales similar in form and markings to 

 those of both these species, but more delicate than either. An- 

 terior dorsal fin slightly in advance of ventrals ; posterior dorsal 

 as much forward of anal fin. 



« Radial formula, A.D. 7 ? ; P.D. 5 ; C. 22 ; A. 6 ; V. 9 ?." 



In the course of the preceding history of the gradual discrimi- 

 nation of the forms which constitute the genera Ccelacanthus and 

 Undina, the following species have been mentioned: — 



Genus. 



Species. 



Formation. 



Ccelacanthus 



Undina 



1. lepturus, Agassiz. 



2. Phillipsii, Agassiz. 



3. robustus, Newberry. 



4. brnatus, Newberry. 



5. elegans, Newberry. 



6. granulatus, Agassiz. 



7. Hassice, Miinster. 



8. caudalis, Egerton. 



9. minor, Agassiz. 



10. striolaris, Miinster. 



11. Kohleri, Miinster. 



Carboniferous. 



Permian. 



Triassic. 



0- 



Oolitic. 



Besides these there are Ccelacanthus gracilis, Ag. of unknown 

 locality and formation, and the so-called " Ccelacanthus " Munsteri, 

 which must be excluded from the genus Ccelacanthus. 



To the important question, how many of these nominal species 

 are truly distinct, and what are their diagnostic characters, I must 

 confess myself unable to give any satisfactory reply. 



I have examined the specimens originally named Ccelacanthus 

 lepturus by Agassiz, in Lord Enniskillen's collection, and I enter- 

 tain no doubt that the specimens from the Staffordshire coal-field 

 described in the present decade are specifically identical with these; 

 but I can find no certain_diagnosis by which this species is to be 

 distinguished from the C. elegans of Newbery (though I by no 

 means affirm the identity of the two), and I have not seen C. Phil- 

 ipsii, C. robustus, and C. ornatus. 



