Miscellaneous. 2G7 



central cavity, bounded by a few endodermic cells. Beyond the 

 latter we see the intermediate lamella, then some well individual- 

 ized ectodermic cells, larger than the others (these are the mother 

 cells of the testis) ; and finally the whole is covered by the ordinary 

 ectodermic cells. Tn the cavity of the gonangium, at its base, are 

 young gonophores, in which we find, from within outwards, a diver- 

 ticulum of the cavity of the blastostyle, epithelial endodermic cells, 

 the intermediate lamella, a small cellular mass of a horseshoe shape, 

 originating from a few differentiated ectodermic cells, and, lastly, a 

 layer of ectodermic cells. The little mass is the young testicular 

 tissue. The different gonophores have the same constitution, with 

 the exception of the development of the tissue, which gradually 

 acquires a larger and larger volume. In the uppermost gonophores 

 all the elements which surround the mature testis are in process of 

 atrophy. The conclusion is that the spermatozoids originate from 

 the ectoderm. 



In the pedicle of a female gonangium we find at the base one or 

 two large endodermic cells projecting into the gastro vascular cavity, 

 having a large nucleus and no vibratile flagellum, in fact presenting 

 all the characters of young ova of the gonophores. At the upper 

 extremity of the pedicle we see one or two differentiated endodermic 

 cells, but with no direct connexion with the gastrovascular cavity, 

 as two or three small endodermic cells cover them. Further up, 

 towards the base of the cavity of the gonangium, the ccenosarc gives 

 origin to lateral diverticula. One of them presents in its interior 

 a small cavity, the cavity of the ca3cum of the blastostyle, bounded 

 by a series of endodermic cells. To the outer surface of this layer 

 is attached a young ovum. The intermediate lamella passes above 

 this ovum ; and further out is the ectodermic lamella. In the upper 

 gonophores the same conditions exist, but the ova become more and 

 more voluminous. When the ovum is mature the tissues surround- 

 ing it are in process of atrophy. The endodermic origin of the ova 

 is therefore evident. 



Bringing together these observations and those of E. van Beneden 

 and Bergb, I conclude that in the family C amp amdar idee the sper- 

 matozoids are developed at the cost of the ectoderm, and the ova at the 

 expense of the endoderm. — Comptes Rendus, Jan. 5, 1880, p. 43. 



On the Plants which serve as the Basis of various Curares. 

 By M. G. Planchon. 



From the data now acquired it may be regarded as established 

 that the plants which serve as the basis of the curare poison all 

 belong to the genus Strychnos. The species of other families which 

 enter into its composition only play a secondary part. 



We know of four distinct regions which are centres of the pre- 

 paration of curare ; and for each of them we may indicate a principal 

 plant which of itself explains the effects of the poison. These are, 

 in the order of the dates at which they became known : — 



1. British (Juiana. furnishing the curare of the Macusis Indians. 



