MACROPOMA SUBSTRIOLATUM. 39 



specimen (belonging to the Earl of Enniskillen), which best dis- 

 plays these structures. 



The resemblance of the branchial apparatus of Macropoma 

 to that of Ccelacanthus is still further increased by the large 

 spatulate bone, which, in Macropoma, terminates the median part 

 of the branchial skeleton posteriorly. No specimen has exhibited 

 the anterior moiety of the median branchial skeleton, so that I 

 am unable to say whether it has or has not the form of a crucial 

 bone. 



I have not been able to procure detached teeth of Macro- 

 poma for microscopic examination. The bases of even the largest 

 teeth are perfectly smooth, and present no longitudinal grooves or 

 foldings. 



Macropoma substriolatum, Huxley (Plate IX. and X.). 



I have abstained hitherto from referring to a specimen of a 

 fossil fish to which Sir Philip Egerton refers in the following 

 terms, in the note at p. 19 the " Preliminary Essay " of Decade 

 X :— 



" In the Woodwardian Museum, at Cambridge, there is the head and 

 part of the trunk of a Ccelacanthus, from the Kimmeridge clay at 

 (Tottenham. The head shows the frontals, prefrontals, and lower jaw, 

 with the tympanic attachments. The glossohyal plate is double, as in 

 Holoptyehius. The scales are roughly undulate, coarser in pattern than 

 in Vhdina, Ccelacanthus, and Holophagus, hut not absolutely tuberculate, 

 as in Macropoma. One fin is preserved, probably the left pectoral. It 

 is lobate, broad, and strong. The operculum is triangular, the frontals 

 short, and the prefrontals descend at an abrupt inclination." 



PI. IX. represents the ventral surface of the body of the 

 Ccelacanth fish of which Sir Philip Egerton speaks, of the size of 

 nature. 



It is covered v;ith large, thin, cycloidal scales, each of which 

 is divided into a large smooth region, overlapped in front and on 

 each side by the neighbouring scales, and a comparatively small 

 free part, which presents numerous close-set elongated dots, or 

 short ridges, of enamel. The dots and ridges are distinct, and 

 their long axes are roughly parallel with that of the body, though 

 the lateral ones sometimes show a certain tendency to diverge 

 from the long axis of the scale itself. 



The left pectoral fin (P) is very well shown, and exhibits, at fewest, 

 fifteen fin-rays, the bases of which are so disposed as to inclose an 

 oval " lobe," which is completely covered by small scales, not 

 more than half, or a third, as large as those of the body, but pos- 

 sessing the same ornamentation. 



The proximal ends of the fin-rays are unarticulated, but seem 

 to be hollow ; distally they become broader and flatter, and then 

 narrow to points, without becoming longitudinally subdivided. 

 Rather more than the distal half of each, apparently, was divided, 

 transversely, into short broad joints. 



The surfaces of these fin rays are quite smooth. 



