72 BULLETIN : MUSEUM OF COMPAKATIVE ZOOLOGY. 



Species. Radial Formulae. ^ Scales of 



LiATERAL Line. 



L. atrox Leidy D. 8 ; C. 12 ; A. 8 ; P. 6 50-60 



L. simplex Leidy D. 7 ; C. 12 ; A. 7 + 1 circa 45 



L. tristoechus ( BL and Sch.) D. 7-8 ; C. 12 ; A. 8 ; P. 6. 60 



L. tropicus Gill D. 8; C. 12 ; A. 8 ; P. 6. 52-54 



L. plati/stomus Uaf. D. 8; C. 12;A. 8; P. 6 56 



L. osseus (Linn.) D. 8 ; C. 12 ; A. 7-9 ; P. 6. 62 



Scales.— The body armoring is excessively heavy, being on a par with that of 

 the head, and recalling the powerful dermal defences of Lepidoius maximus from 

 the Upper Jura. In fact, these two species probably have the strongest scaly coat- 

 ing of all fossil ganoids. Owing to flexure of the body in the present specimen, 

 with consequent disturbance of the squamation anteriorly, it is difficult to count 

 the longitudinal or even transverse scale-series with accuracy. There are no 

 conspicuously marked scales along the dorsal ridge by which the median line 

 of the back can be determined ; but making all due allowance for displace- 

 ment, the number of longitudinal series in the middle of the body may be set 

 down at between 18 and 20, and of transverse oblique series counting along 

 the lateral line at between 50 and 60. A very large anal scale marks the posi- 

 tion of the vent. The exposed surface of most of the«cales lying between the 

 tail and middle of the body is smooth, but the posterior margin is strongly 

 fimbriate. Some of the scales lying in advance of the pelvic fins are smooth, 

 but the majority have their central portion ornamented with punctge, pittings, 

 or channellings, and interspersed with these are occasional papillae. The lateral 

 line in the present specimen is inconspicuously marked. To give enlarged 

 figures of separate scales is hardly considered worth while, owing to the exten- 

 sive series illustrated by Leidy and Cope. Those figured by Cope (Rept. U. S. 

 Geol. Surv. Temt., Vol. III. Plate II, Figures 8, 10-12) show the typical orna- 

 mentation as well as any, and Figures 47 and 48 show the highly sculptured 

 postclavicular plates. 



Vertebrae. — The vertebral column is traceable for the greater portion of its 

 length, although it protrudes only at intervals through the mass of scales so as 

 to exhibit the individual centra. For views of detached vertebra} reference 

 must l)e had to the works of Leidy and Cope already cited. Stout displaced 

 neural and haemal spines are visible in places along the extent of the vertebral 

 column, and in some places ribs are to be distinguished. 



Coprolite. — Accompanying the specimen is a cylindrical coprolite 13.5 cm. 

 long and 5.5 cm. in diameter, which is stated by the collector to have been 

 found in close proximity to the fish. That it is of piscine origin admits of no 

 doubt, and it could hardly have been voided by a smaller species than that 

 under consideration. Its outer surface is marked with a few irregularly spiral 

 folds, but is otherwise smooth. No large hard particles are to be distinguished, 

 and the whole mass bears evidence of very thorough digestion. 



