froui the Coal Me(i.<i(r<\< of LancasJiire. 409 



by the regular scales of the hody. Passing forward at right- 

 angles to tlie ventral end of the eleithruni is a large 'Mnfra- 

 clavicle " (true claviule) ; it is cone-shaped, tai)ering slightly 

 to a round(>d anterior end, and by the flattening ot the 

 pectoral arch it has been pushed down a little below the 

 natural ventral margin of the fish. The right side of 

 the nodule shows a cast of the inner face of the eleithruni, 

 with the hollow for the scapulo-coracoid cartilages close to 

 the junction with the infraclavicle. 



The squaniation of the body is well-preserved only in a 

 few regions ; for the most part the true surface of the scales 

 has been lost, and the impressions are granular and not too 

 easy to decipher. The scales are rhomboidal, large, and in 

 some regions exceptionally deep. Strongly developed ridge- 

 scales occur along the mid-dorsal and mid-ventral borders ; 

 the ventral ridge-scales are ])aired as far back as to the pelvic 

 fin, but the dorsal row is single, with each scale (to the dorsal 

 fin at any rate, and probably to the tail) produced back- 

 wards into a long, very acuminate spine. About twenty-four 

 transverse rows of scales are shown, and in the abdominal 

 region there appear to be six scales in eacb row below^ the 

 dorsal ridge-scales. Of these six the upper three cover two- 

 thirds of the total depth of the body, and each of them bears 

 a tubercle at or near its posterior ventral angle. There are 

 thus three longitudinal lines of tubercles on the flanks of 

 this fish. The upper and lower lines die out on the tail- 

 shaft, but the middle line of tubercles, which throughout is 

 much the most strongly developed, apparently extends to the 

 caudal fin. These prominent middle tubercles are borne by 

 the scales of the lateral line, which shows as a raised tube- 

 like ridge on the last few scales, but is marked more 

 anteriorly by deep notches. The scales next below the 

 lateral line are, in the abdominal region, the deepest of all. 

 Below them again, in each transverse row (but not behind 

 the anal fin), come two scales of more ordinary form, and 

 then the ventral ridge-scales. Between the pelvic and anal 

 fins the paired ridge-scales are replaced by enlarged median 

 scales, much like the anal scales commonly seen in the 

 Semionotidse. 



Nothing is seen of the pectoral fin, but some portion of 

 each of the others is preserved, though none is at all nearly 

 complete. The dorsal fin is placed above the region where 

 the body passes into the tail-shaft. In advance of it the 

 dorsal ridge-scales are greatly enlarged and produced into 

 very strong spines. By a rapid tran:?ition these pass into 



