EASTMAN: FOSSIL LEPIDOSTEIDS. 75 



in the total length, in L. platystomm and L, tristaechus three and one half, and 

 in L. osseus with its specialized snout, but three times. The armoring of the 

 present species is everywhere lighter and simpler than in the massive L. atrox, 

 from which it is readily distinguished by its smooth scales with non-finibriate 

 posterior borders Another peculiarity which is probably of specific import- 

 ance consists in the marked elongation of the flanked scales beginning with the 

 series in advance of the anal tin and continuing to the tail. Many of the scales 

 thus affected are twice as long as they are deep, which accounts for there being 

 only 15 oblique transverse scale-series between the base of the tail and base of 

 the anal tin, as compared with 21 such series in L. osseus, and 23 in L. tristcz- 

 chus and L. atrox. Owing to flexure of the body with attendant disruption of 

 the squaraation, it is impossible to state accurately the number of oblique rows, 

 but there were at least 45 of them, and possibly 50. 



The head appears to have been nearly severed from the body and turned 

 completely over prior to fossilization, thus exposing the visceral surface to 

 view. This was not accomplished without injury or displacement of certain 

 parts, as witnessed by the position of the left palatine, which shows its oral 

 surface adjacent to the right frontal (above in the figure), while the right man- 

 dibular ramus, hyoid arches, and interoperculum are transported to the opposite 

 side of the head (below in the figure) Back of the last-named element 

 is seen from visceral aspect the left clavicle, a strong bone similar in all 

 respects to that of recent gars. The interoperculum ditt'ers from the correspond- 

 ing bone in L. atrox in wanting a postero-inferior process, and it is relatively 

 much lighter as well as somewhat smaller. Neither of the maxillae are pre- 

 served, and but one of the man(lil)ular rami ; this, the right-hand one, is 

 turned downward so as to conceal most of the teeth, but the articular facets are 

 well shown, and appear exactly as in L. tristoichus. Little more can be said ot 

 the cranial bones, owing to their confused position and the fact that none of 

 them diff"er in any appreciable respect from those of recent species. 



Of the vertebral column fourteen centra lying in natural order are visible back 

 of the head, their length increasing rapidly from 0.55 cm., beginning with the 

 first, to 0.85 cm. The fins are relatively weaker than in L atrox, especially 

 the caudal, which has fewer short rays , and the dorsal and anal are more 

 remote. The radial formula is as fellows : D. 7 (-8?); C. 12; A. 7 (-8 I). 



Table of Measurements. 



Length of mandibular ramus 10 + cm. 



Length of interoperculum 5.2 



Length of hypohyal ... 0.8 



Length of ceratohyal 2.5 



Length of epihyal 1.0 



Height of clavicle ,...., 6.2 



Height of caudal pedicle 6.0 



Width of basioecipital concavity 1.2 



Distance from basioecipital concavity to vomer .... 16.0 



