G. R. Wieland — Upper Cretaceous Turtles. 443 



(a) Bony plates : — Marginals, 11 pairs, very heavy; nuchal, 

 large, of sub-pentagonal outline, without a nether process, but 

 with costiform processes sometimes perforating the entire 1st 

 marginals (A. tardus) ; neural series with but seven or eight 

 members — the 9th or post neural being present with suppres- 

 sion of the 7th, or both 7th and 8th ; pygal single as in 

 Adoous / pleuralia very heavy with medium to slight develop- 

 ment of the rib capitulee. 



(h) Hornshields. — A medium-sized nuchal and twelve pairs 

 of marginals with the inner or marginalo-costal suture not 

 rising onto the pleurals, as in Adoous, but traversing the 

 marginal plates throughout (except in the single species A. 

 mascidinus, where the penult and h'nal or pygal shields respec- 

 tively overlap the 8th pleural and pygal plate. 



Plastron. — Of medium size, without fontanelles and very 

 heavy with the strong bridge suture extending from the pos- 

 terior end of the 3d to the anterior end of the 8th marginal. 

 Entoplastron large, of sub-isosceles triangular to rhombic out- 

 line. Epiplastral border rounded ; anal region acuminate in 

 every known species — not rounded as in Adoous. 



AgompTius is held to be distinct from the earlier proposed 

 genus Adoous mainly because of the position of the marginalo- 

 costal suture on the marginals, the very characteristic form of 

 the plastron, and the enormous thickness of shell. Although 

 some of the imperfectly known species may prove to intervene 

 and bridge these gaps — not large when taken singly, — it 

 appears at present that they uniformly separate an Agomphid 

 series of closely, related, mostly small turtles ranging from the 

 Upper Cretaceous into the Eocene. Therefore, as both Adoous 

 and Agomphus are numerous in species, it would seem to be 

 much the better policy to retain the latter genus so long as not 

 definitely proven to merge into the former. The species 

 respectively assigned to these two closely related genera of the 

 Adocidse therefore are : 



1. Adocus (Emys) beatus (Leidy) Cope. 



2. " agilus Cope. 



3. " pravus (Leidy) Cope. 



4. " syntheticus Cope. 



5. " punctatus Marsh. 



6. Agomphits (Emys) turgidus (Leidy) Cope. 



7. u " firmus (Leidy) Cope. 



8. " (Amphiemys) oxysternum (Cope) Hay. 



9. " p>etrosus Cope. 



10. " (Adocus) pectoralis (Cope) Wieland. 



11. " tardus Wieland. 



12. " mascidinus Wieland. 



