CCELACANTHUS CAUDALIS. 23 



The second dorsal fin (D 1 ) contains 14 rays ; its basal breadth 

 is 02 in., its length not less than 0*5 in. The rays are slender, 

 and only become jointed towards their extremities. The peculiar 

 forked interspmous bone of this fin is not in its place, but I 

 believe I can trace indications of it in the space between the 

 lower edge of the first dorsal and the ends of the neural arches. 



The first dorsal (Z>) is fully 0'8 in. long and 0*25 in. broad at the 

 base ; 11 or 12 fin rays can be counted, which are much stronger 

 than those of the other fins, and, like the others, are only jointed 

 at their tapering distal ends. I observe no spine-like tubercles 

 upon these, anymore than upon the other, fin-rays. The impres- 

 sion of the broad interspinous bone of this fin is plainly visible 

 in situ. 



About 23 close-set superior, or neural, ossified arches, occupying 

 about 0*5 in., may be counted immediately behind the head. The 

 spinal column is there interrupted for nearly the same distance, 

 and a solitary neural arch is seen thrown down out of the series. 

 Behind this point the neural arches are undisturbed, and opposite 

 them, on the ventral side of the body, the series of subvertebral 

 arches commences. That the point at which these commence is, 

 in fact, part of the caudal region is shown by its relation to the 

 position of the ventral fins. More than 40 neural arches can be 

 counted behind the break, and there were therefore probably not 

 fewer than 80 in the whole series. The number of subvertebral 

 arches cannot be satisfactorily ascertained. There are no ribs 

 in the dorsal region. 



I am inclined to think that a distorted and V-shaped elevation 

 which occupies the portion of the cavity of the body immediately 

 under the anterior dorsal fin, is the remains of the ossified air 

 bladder. 



The head is so crushed that nothing definite can be made of 

 its structure. The strong pectoral arches are discernible imme- 

 diately behind it, but they also are much crushed. 



No sculpture is visible upon what remains of the cranial bones. 



IV. Ccelacanthus elongatus, Huxley. 



The specimens to which I have applied this name, rather 

 because I cannot identify them with any other species than be- 

 cause they have good positive characters of their own, are all mere 

 impressions in shale, from Ballyhedy, near Ballinhassig, county of 

 Cork, Ireland. They were sent to me by my colleague, Professor 

 Jukes, the local director of the Geological Survey of Ireland, and 

 are now in the collection of that Survey. 



No. 1. The specimen represented in PL V., Jig. 6. 



This fish was probably about 3*5 in. long when entire. The 

 head is somewhat less than one inch long, and appears more elon- 

 gated and tapering in proportion than in the other species. 



The anterior edge of the dorsal fin is 0*65 in. from the head, 



