20 BULLETIN 151, UNITED STATES NATIONAL MUSEUM 



Genus LYCOPHIDION Dumeril and Bibron 



LYCOPHIDION CAPENSE (Stnith) 



Lycodon capensis Smith, 1831, South Afr. Quart. Journ., vol. 1, No. 5, p. 18, and 



1838, Illus. Zool. S. Africa, vol. 3, pi. 5. 

 Lycophidium capense Boulenger, 1893, Cat. Snakes, Brit. Mus., vol. 1, p. 339. 

 Lycophidium jacksoni Botjlenger, 1893, Cat. Snakes Brit. Mus., vol. 1, p. 340, 



pi. 21, fig. 3. (Type localities Kilimanjaro, T. T., and Lamu Id., K. C.) 



1 (U.S.N. M. 40885) Wambugu, K. C. (Sm. Afr. Exped.) 1909. 



2 (U.S.N.M. 40966-7) Nairobi, K. C. (Sm. Afr. Exped.) 1909. 



I (U.S.N.M. 41133) Mount Kenya to Fort Hall, K. C. (Sm. Afr. 



Exped.) 1909. 



1 (U.S.N.M. 42023) ? Lake Sirgoit, K. C. (Sm. Afr. Exped.) 1909. 



1 (U.S.N.M. 42049) Kenya Colony. (Sm. Afr. Exped.) 1909. 



1 (U.S.N.M. 48590) Mtoto Andei, K. C. (Heller) 1911. 



1 (U.S.N.M. 49388) Kaimosi, K. C. (Heller) 1912. 



1 (U.S.N.M. 66928) Between Abyssinia and K. C. (Mearns) 1912. 



All agree in having 17 scale rows except No. 66926, which has 16; 

 ventrals, 171 to 193; siibcaudals, 28 to 39. The largest specimen 

 (No. 66928) measures 467 (420 + 47) mm. and the smallest (No. 

 49388) 203 (180 + 23) mm. 



For a considerable time I have entertained doubts as to the status 

 of L. jacksoni Boulenger which was described from two smallish 

 snakes, measuring 192 and 222 mm., respectively. All of its char- 

 acters as enumerated by the author were already within the recog- 

 nized range of variation of L. capense, except that in L. jacJcsoni the 

 diameter of the eye was "not greater than its distance from the 

 mouth," while in L. capense the diameter was "considerably greater." 



The present series may be sorted into two ^Toups — those with 

 the diameter of the eye "just greater" and those where it is "much 

 greater"; if these are then arranged according to length it will be 

 found that those from 203 to 371 mm. have the diameter "much 

 greater," while those from 389 to 467 mm. are of the "just greater" 

 group — that is to say, the proportionate largeness of the eye is an 

 age character, the eye being larger in the young and diminishing 

 proportionately with age. In the types of L. jaclcsoni the adult 

 condition seems to have been attained while the snakes were still of 

 small size, yet it is hardly possible to keep them distinct on such 

 grounds when typical L. capense as well as those where the eye 

 diameter corresponds to L. jaclcsoni occur between the tj'^pe localities 

 of the latter. 



After writing the foregoing I communicated with Mr. H. W. 

 Parker who I knew had been recentlj^ engaged in studying the genus. 

 He replied that in his revision, publication of which is likely to be 

 delayed, he had placed L. jacksoni in the synonymy of L. capense 

 and has very kindly allowed me to quote liis reasons here. He 

 writes: "i. jaclcsoni Boulenger differs only from L. capense in the 



