STEIIEOGENYS CROMElil. 
299 
of neural bones cannot be determined, but it seems certain that, as in the next species, 
the neural series is separated both from the nuchal and pygal bones by the junction 
in the middle line of the anterior and posterior pairs of costals respectively. There 
are eight pairs of costal bones, but the number of marginals cannot be made out. 
The nuchal bone is large, but much narrower than in S. lihyca, so that, as 
lleinach has pointed out, it seems improbable that the anterior vertebral shield was 
narrower than the nuchal as in that species. Scarcely any trace of the epidermal 
shields is preserved, but the two middle vertebrals seem to have been large and 
roughly hexagonal in outline. 
Text-fig. 9G. 
'5 nal siye 
Carapace and plastron of Stereogenys cromeri: A, carapace; B, plastron. 
Enf., entoplastral bone ; g., gular shield ; Ey.p., hyoplastral bone ; Hyp.p., hypoplastral bone ; ig., inter- 
gular shield; Msp., mesoplastral bone; n., humeral shield; Am., nuchal bone; p., pectoral shield; 
Xi.p., xiphiplastral bone. nat. size. 
(From the Ann. & Mag. IXat. Hist. [7j vol. xi.) 
The plastron (text-fig. 96, B) is relatively large : the bridge is long, being in the 
specimen described about 20‘5 cm. in length ; while the length of the anterior free 
lobe is only 11-5 cm., and that of the posterior lobe about 15 cm. The anterior 
border is slightly concave in the middle line. The entoplastral [Ent.) is large and 
rhomboidal, the sides being sometvhat convex. The sutures between the epiplaslrals 
and hyoplastrals are concave in front and run forwards, terminating on the edge of 
2p 2 
