264 MESSRS. HANCOCK AND HOWSE 



marginal fulcra, plates or scales (/), and the double row of 

 rhombiform scales (e) behind, as well as the fin-rays of both divi- 

 sions, are very perfect, the latter displaying their bifurcated ex- 

 tremities stretched out. The lobes are about equal in length, if 

 measured from the root, along the axis. In this way they are 

 one inch and a quarter in length; but if measured along the 

 posterior margin, the upper lobe is nearly one inch and a quar- 

 ter long, and the under lobe only seven-eighths of an inch in 

 length. The width of the tail from tip to tip is upwards of one 

 inch and three-quarters. The specimen measures four inches 

 and three quarters in length, and one inch and seven-eighths in 

 depth. This specimen remains in the possession of Mr. Duff, to 

 whom we are indebted for the discovery of these and many 

 other interesting fossil remains. 



Our third specimen (PI. X., fig. 3) is the only one which lies 

 with its right side exposed ; all the other three have the left side 

 uppermost. This measures in length, including the tail, and 

 making allowance for what is wanting in front, four inches and 

 three-quarters, and in depth at the widest part two inches and 

 one-eighth ; and it is chiefly distinguished by the large portion 

 that remains of the dorsal fin. 



The head does not appear to have been much injured when 

 the specimen was deposited ; but unfortunately the upper and 

 frontal portions are broken away. The orbit (u), however, is 

 well marked ; and so are the boundaries of the opercula (s), the 

 posterior contours of which are quite distinct. Three or four of 

 the ventral plates (m) are seen in their proper places in front of 

 the anal fin, sending upwards their columns, which exhibit well 

 their compound and twisted appearance. Some of them reach 

 the lateral plates near the occiput. The great abdominal rods 

 (o) are seen in connexion with the posterior plate inclining up- 

 wards and backwards. 



The plates and rods are much displaced ; but, notwithstanding, 

 their connexions and characters are in some places well seen, 

 particularly the relationship of the lateral plates to the lozenge- 

 shaped central plates, or areas, on a few of which the median 



