10. TROPIDONOTUS. 237 



q. 2 (Sc. 23 ; V. 15.) ; C. 5:j). Hamman R'irha, Dr. J. Anderson [P.]. 



Algeria. 



r-s. Yg. (V. 153, 150; C. St. Barbe, Algeria. Dr.R.Blanchard fP.]. 



56,60). 



t. 2 (V. 153; C. 50). Biskra. 



M. Yg. (V. 152; C. 52). Tiimnirt, Algerian Dr.R.Blanchard [P.]. 



Sahara. 



v-y. $ (V. 152, 154; C. 50, Tunis. Mr. Fraser rC.l. 



47), hgr. $ (V. 151 ; C. 



50),&vg. (V.147; C.57). 



z. 2 (Sc' 23 ; V. 157 ; C. N. Africa. Zoological Society. 



58). 



a. Skull. Algeria. 



B. Two yellow or reddish longitudinal dorsal lines in additioii to 

 the usual markings, {N. oceUata, Wagl., C. aui-oUneatus, Uerv,, 

 T. ojjpelu, Boie, T. chersoides, D. & B.) 



a. Hgi-. c? (V. 149 ; C. ?). Mountain streams of Col. Irby [P.]. 



Algeciras. 



h. (S (V. 165; C. 72). Alemtejo, Portugal. Dr. II. Gadow [C.l. 



c. $ (V. 154 ; C. 53). Tangier. Mr. Fraser [C.]. 



d. Yg. (V. 157; C. 62). St. Barbe, Algeria. Dr.R.Blanchard rP.1. 



e. 2 (V. 153 ; C. 49). Tunis. Mr. Fraser [C.l. 



/. c^ (V. 154; C. 59). Duirat, Tunisia. Dr. J. Anderson [P.]. 



37. Tropidonotus validus. 



Regina valrda, Kennicott, Proc. Ac. Philad. 1860, p. 334; Cope.Bidl 



U.S. Na-LMiis. 110.^2,^.74. (ISS7). 

 Tropidonotus celseno, Cope, Proc. Ac. Philad. 1860, p. 341, and 1861 



p. 298. 



tephropleura, Cojye, II. cc. 



validus, Cope, I. c. p. 342 ; Cones, Wheelers Pep. Surv. JV. lOOth 



Mer. V. p. 612, pi. xxi. (1875). 

 quadriserialis, Fischer, Verh. nat. Ver. Hattih. (2) iii. 1879, p. 82, 



pi. i. fig. 2. 



leberis, var. validus, Garm. N. A^n. Pept. p. 28 (1883). 



sirtalis, var. quadriserialis, Garm. I. c. p. 140. 



Regina quadriserialis, Cope, BtiU. U.S. JS'at. Mies. no. 32, p 74 



(1887). 

 Natrix valida, Coj)e, Proc. U.S. Nat. Mus. xiv. 1892, p. 670. 



Eyes rather small. Rostral broader than deep, visible from 

 above ; nasal usually semidivided ; internasals much narrowed 

 in front, longer than broad, as long as or a little shorter than 

 the prajfroutals ; frontal twice as long as broad, as long as its 

 distance from the end of the snout, shorter than the parietals • 

 loreal as long as deep, or longer ; one or two prae- and three 

 (rarely two) postoculars ; temporals 1 + 2 or 1 + 3 ; eight upper 

 labials, fourth and fifth entering the eye : five lower labials in 

 contact with the anterior chin-shields, which are a little shorter 

 than the posterior. Scales in 19 (rarely 21) rows, outer row 

 faintly keeled. Yentrals 136-147 ; anal divided ; subcaudals 

 66-83. Greyish or olive-brown above, uniform or with lont^i- 



