22 OSTEOLOGY OP SCOMBROID PISHES 



Two series of long, slender bones lie just beneath the skin and in- 

 case the body, one series above and one below the middle of the side. 

 The upper series is composed of the epipleurals, which curve outward 

 to the skin and then upward nearly to the dorsal. The lower series is 

 an extra intermuscular ossification, and is perhaps not present in the 

 young, as is the case with a similar ossification in the genus Chanos. 

 The first two vertebra bear epipleurals only. On the third vertebra 

 and some of the succeeding ones the epipleurals and ribs join the verte- 

 brae together, with their bases connected, but a short distance back the 

 epipleurals lose all connection with either ribs or vertebra and lie 

 loose in the intermuscular connective tissue. The last two or three 

 vertebras are as in Scomber, not abruptly shortened as in most of the 

 Scombridae. There is no trace of a lateral caudal keel. The hypural 

 bears a large urostyle. 



The upper ends of the interneurals of the spinous dorsal are lat- 

 erally expanded, and probably represent the anchylosed baseosts. No 

 separate bony baseosts are present in any of the fins. The bases of 

 the caudal rays are not deeply divided, nor are the rays widely diver- 

 gent as in most of the Scombridae. 



A skiograph of Epinnula magistrates from a specimen in the U. S. 

 National Museum shows the number of vertebras to be 15 + 17 (count- 

 ing the hypural) ; the ribs are borne at the tips of the abdominal 

 haemal spines ; the body is not incased in a series of intermuscular rays, 

 as in Promethichthys, and the ventral fins are attached to slender pelvic 

 bones which extend between the clavicles. 



LEPIDOPUS. 



A specimen of L. caudatus from the Canary Islands, measuring 3 

 feet in length. 



In this form the supraoccipital crest is far anterior to that of 

 Promethichthys. As viewed from the side of the cranium it rises as a 

 stout triangualr process far above the rest of the skull, with its sharp 

 apex directed upward. It is over the posterior part of the orbital cav- 

 ity, or nearly a fourth of the distance from the occipital condyle to 

 the tip of the vomer. The frontals form the anterior part of it. The 

 ridges, which in Promethichthys are low, and run from the front of the 

 supraoccipital obliquely to intercept the temporal crest in Lepidopus, 

 are high, sharp ridges, starting at the apex of the supraoccipital crest 

 and running more directly forward. Deep between them is a small 

 median ridge representing the front part of the supraoccipital crest. 



