- ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 369 



aperture of the oviduct (epitJielJiugel) gives rise to the ectoderm of the 

 embryo and to the wall of the placenta ; the walls of the follicle are 

 developed into the mesodermic organs of the embryo, the intestinal 

 canal, pericardial cavity, and nervous system, together with the " roof" 

 of the placenta and vascular tufts; in this group the oviduct is 

 transitory and soon disappears. 



In the second group (Gymnogonce) there is no outer fold; the 

 inner fold (epiihelhugeV) is transitory and the placenta is formed from 

 the follicle or is merely transitory and commences to degenerate by 

 assuming the appearance of a protoplasmic network in which the 

 separate cells are indistinguishable ; the oviduct persists, either taking 

 a share in the formation of the embryo {S. democratica) or serving as 

 a brood cavity (S. hicaudata) for a short time and then disappearing. 



The developmental process of Salpa is so peculiar that it is very 

 difficult to compare it with other known types of development ; the 

 fact that the follicular cells take a share in the production of the 

 embryo (the process of development being therefore both sexual and 

 asexual) is not, however, confined to this group. Lankester has 

 described a very similar state of things in Cephalopoda, where the 

 " inner capsular membrane " — the follicle itself — grows into the ovum 

 and partly forms the nutritive yolk ; recent researches also into the 

 Vertebrata tend to show that the yolk is partly formed from the cells 

 of the follicle. Salpa hicaudata appears to represent the most simple 

 development of all the species, while further complications, such as the 

 formation of a part of the embryo by cells of the oviduct, tend to re- 

 move other Salpce further from the normal mode of development 

 exhibited in the animal kingdom. 



Budding of Ancliiiiia.* — A. Korotneff has observed a colony of 

 Anchinia to be covered with small corpuscles of two kinds, and with 

 two modes of movement ; one was wavy in outline, the other pyriform ; 

 the former had vesicular contents and moved rapidly by means of 

 lobate pseudopodia, very much like those which are seen in such a 

 form as Amoeba palustris. In the second form the pseudopodia, which 

 were confined to the narrower end, were fi^ne and filamentar ; their con- 

 tents were compact and not granular, and there was an aggregation of 

 corpuscles at their centre ; they appeared to be completely analogous 

 to the primitive buds found by Uljanin in Doliolum, and were not, as 

 the other kind of bodies, unicellular, but multicellular. The author 

 has been able to convince himself that the simpler are developmental 

 forms of the more complex forms, and that the change is effected in 

 the following way. The nucleus of the cell gradually divides, and at 

 the same time the body of the cell loses its vesicular character and 

 becomes finely plasmatic ; a separation of ectoderm and endoderm is 

 very early apparent ; the cells of the body gradually grow, and endo- 

 dermal cells with large vesicular nuclei become apparent — these form 

 the future ovary, while the remaining three cells go to form the rudi- 

 mentary intestine. As the ectodermal becomes separated from the 

 endodermal layer, a lumen appears which is the true body-cavity. 



* Zeitschr. f. Wiss. Zoo!., xl. (1884) pp. 50-61 (2 pis.). 

 Sev. 2.— Vol. IV. 2 C 



