THE MICROSAURIAN FAMILY SAUROPLEURID.K. 157 



clavicle are taken as the principal specific characters. From the other species of 

 the genus the present form differs in its more slender elements of the ventral armor 

 and in the form of the skull. The ribs are not clearly defined. 



MEASUREMENTS. 



mm. mm. 



Median length of skull 70 Length of mamlibular tooth . . i .5 



Posterior width of skull. ... 40 Length of entire specimen. . 150 



Anterior width of skull 20 Width across belly, maximum . . ... 47 



Length of jaw 50 Length of interclavicle. . . 27 



Anterior width of jaw 7 Width of interclavicle 13 



Posterior width of jaw 12 Width across posterior extension. . 4 



Sauropleura digitata Cope. 



COPE, Proc. Phila. Acad. Nat. Sci., p. 216, 1868. 



COPE, Trans. Am. Phil. Soc., xiv, p. 15, 1869. 



COPE, Geol. Surv. Ohio, n, pt. n, p. 403, pi. xxxvii, fig. l, 1875. 



Type: Specimen No. 8004 G, American Museum of Natural History. 



Horizon and locality: Linton, Ohio, Coal Measures. (Plate 20, fig. 4.) 



This species is represented by a single individual which is quite distinct from 

 other members of the genus. The specimen has been spread over a surface of the 

 coal, and exhibits ventral armature, dorsal region with ribs, and anterior and pos- 

 terior limbs. Skull and caudal region not present. 



The ventral armature is arranged in parallel lines directed obliquely forwards 

 and continuous on the median line, forming there a chevron. The individual ele- 

 ments are oat-shaped, and acuminate at both ends. They are moderately imbri- 

 cate in an antero-posterior section. On the pectoral region between the fore limbs 

 the series of scutellae assume different directions, forming chevrons directed back- 

 wards, and forming with those of the belly a complete X. 



The humerus, ulna, and radius are rather stout, and of a size relative to the 

 body, as in common types of existing lizards; the ulna and radius separate. The 

 carpus is cartilaginous ; the digits are 5 well-developed fingers having phalanges in 

 the following numbers, commencing on the inside: 3, 4, 5, 6, 5. The last phalanx of 

 the second is obscured, and it is not positive that the number is as given; it is more 

 probable that it was 4 than 3. The outer toe was more slender than the others; 

 the distal phalanges of all the toes are stout, as in modern Caudata. 



The ribs are long and curved as in reptiles, and jtidging by their distances the 

 vertebras are short; the latter are not well-defined, but there is no indication of prom- 

 inent spines of any kind. The pelvic bones and portions of the hind limbs are pres- 

 ent, but so obscured and confused as not to be easily made out. Enough remains 

 to show that the hind limbs were longer than the fore. Thirteen ribs on one side 

 and twelve on the other are preserved, with short ribs in the sacral region. The 

 specimen is very indistinct and it is difficult for one to be stire of all the characters 

 described by Cope. 



MEASUREMENTS OF THE TYPE OF SAUROPLEURA DIGITATA COPE. 



mm. mm. 



Length of specimen .... 115 Length of radius. ... 10 



Greatest width 80 Length of ulna 9 



Diameter of ventral scute .75 Length of mctacarpal. . 4 



Length of rib 15 Length of fourth digit of hand . . 22 



Width of rib I Length of interclavicle 20 



Length of humerus 20 Width of interclavicle 1 1 



