38 ;Mr. W. 'Wcdekind on Alternation of 



large black rhombs which may be confluent into a zigzag 

 band ; a lateral series of smaller black sj)0t3 ; a A- or A-shaped 

 black marking on the top of the head, the point between the 

 eyes; a black streak on each side of the head, from above 

 the nostril to above the last labial shield ; lower parts 

 uniform yellowish or pale green ; end of tail black or blackish. 



Total length 630 mm. ; tail 85. 



Seveial specimens were obtained by Mr. R. B. "Woosnam 

 on the east side of E-uwenzori, between 6000 and 6500 feet 

 altitude. This fine snake may sometimes be seen coiled up 

 round the stem of elephant-grass 10 feet above the ground. 

 It is viviparous. 



This species is well characterized by its smaller eye, its 

 sharp canthus rostralis, and its smooth or nearly smooth 

 gular scales. 



IX. — Alternation of Generations, Metamorphosis, and 

 Direct Development. By W. Wedekind *. 



In my previous w^-itings on the subject of parthenogenesis I 

 have already pointed out that, in my opinion, so-called asexual 

 reproduction was everywhere the primitive method, and that 

 it is only in the course of phyletic development, through the 

 series — segment, bud, spore, and female and male partheno- 

 ovum, — that at last the ovum needing fertilization and the 

 .«perm belonging to it have arisen therefrom. It follows, 

 llieref'ore, that all organisms with sexual reproduction must 

 be derived from asexual ancestors. According to the bio- 

 genetic law of recapitulation this phylogeny must also very 

 generally have been repeated in the ontogeny, and I would, 

 moreover, venture to assume that in earlier e])ochs the course 

 of the entire ontogeny \\ as not yet by any means so rapid as 

 it usually is to-day. It therefore follows from our theory 

 that the ancestral stage of asexual reproduction must formerly 

 have still been displayed in the development of each indi- 

 vidual, and that it was only gradually that it became more 

 and more suppressed. 



According to this interpretation, then, in the tirst instance 

 from every fertilized ovum at least an asexual generation 

 must again have develoj)ed, and only from this has there 

 arisen once more the ultimate form with sexual reproduction. 



* Translated liv E. E. Austen I'roui the ' Zoologischer Anzeiger,' 

 lid. xxix. Nos. ^A/JU (March 6, I'tOO), pp. 7itO-79o. 



