STEEEOG-ENyS CEOMEEI. 



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 (Mi.) is large, but much narrower than in S. liiyca, so that, as 

 Eeinach 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. 96. 



Carapace and plastron of Stereogenys cromeri: A, carapace ; B, plastron. 

 Ent., entoplastral bone ; g., gular shield ; JHy.p., byoplastral bone ; ffyp.p., bypoplastral bone ; ig., inter- 

 gular shield ; Ms.p., mesoplastral bone ; n., humeral shield ; Nu., nuchal bone ; p., pectoral shield ; 

 Xip., xiphiplastral bone. \ nat. size. 



(Prom the Ann. & Mag. Nat. 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 somewhat convex. The sutures between the epiplastrals 

 and hyoplastrals are concave in front and run forwards, terminating on the edge of 



2q2 



