272 



TRIONTCniDiB. 



Cycloderma senegiilense, A. Dum. Arch. Mus. x. p. 1G8 (18G0). 



petei'sii, Strauch, Chclon. Stud. p. 5G (18G2). 



Cyclanosteus senegalensis, Gray, Pruc. Zool. Soe. 1864, p. 95, and 



1865, p. 422, figs., and Si/pj)!. Cat. Sh. Rept. i. p. 112 (1870), and 



Proc. Zool. Soc. 1873, p. 70. 

 Tetrathvra baikii. Gray, Proc. Zool. Soc. 18G5, p. 324, fig., and 



Siippl. Cat. Sk. Rcpt. p. 110. 

 Baikiea elegans, part., Gray, Proc. Zool. Soc. 1869, p. 222, and Suppl. 



Cat. Sh. Rept. p. 115. 



Carapace and plastral callosities rather finely granulate and ver- 

 miculate ; two neural plates between the first pair of costals ; at 

 least nine plastral callosities in the adult, sometimes more, additional 

 small plates being present on the sides of the epiplastra and between 

 the latter and the hyoplastra ; xiphiplastral plates usually the 

 smallest ; the hyo-hypoplastral and epiplastral callosities developed 

 before the others. Head moderate ; snout short ; orbit nearly 

 equidistant from the nasal and temporal fossae ; interorbital space 

 at least half the greatest diameter of the orbit in the adult ; no 

 protuberance at the symphysis of the mandible. Dorsal disk of 

 young with longitudinal ridges of small tubercles. Olive above, 

 uniform or with small dark spots on the dorsal disk ; head with 

 numerous small light spots ; plastron yellowish, clouded with brown. 



Length of dorsal disk 35 centim. 



Senegambia to Upper Xile. 



a. Hgi'., shell. 



b. Hgr., &kel., imperfect. 



c. Yg., spir. 

 d-f,fj-m. Yg., spir. 

 n. Ad., stffd. 



0, p. Yg., stffd. 



q. Hgr., shell. 

 r, s, t. Ad., skulls. 



u, V, w. Hgr., skulls. 

 X, y. Hgr., shells. 



Gambia. 



Gambia, 

 Senegal. 

 W. Africa. 

 W. Africa. 

 W. Afi-ica. 



W. Africa. 

 W. Africa. 



W. Africa, 







Eari of Derby [P.]. 



of C. petersii.) 

 Earl of Derby [P.]. 



(Type 



Dr. B. Baikie [C. 



Dr. B. Baikie [C 



Dr. B. Baikie [C.]. (Types 



of Tetrathyra baikii.) 

 Dr. B. Baikie [0.1. 

 Dr. B. Baikie [0.]. (Types 



of Baikiea eleqans.^ 

 Dr. B. Baikie [C.]. 



2. Cyclanorbis elegans, 



Baikiea elegans, part., Gi-ay, Proc. Zool. Soc. 1869, p. 222, pi. xv. 

 f. 2, and Suppl. Cat. Sh. Rept. i. p. 115 (1870). 



This species, which is known from quite young specimens only, 

 differs from the preceding in the presence of a strong knob on the 

 inner surface of the symphysis of the mandible, in the larger dorsal 

 dermal tubercles, and in the coloration. Dorsal and ventral disks 

 dark brown, the former with very large irregular yellowish spots, 

 the latter with small round spots of the same colour ; head and 

 chin with closely-set yellowish spots separated by a brown network. 



West Africa. 



o. Yg., .spir. ; h. Yg., stffd. 



W. Africa. 



Dr. B. Baikie [C.]. 

 (Types.) 



