2 Mr. H. J. Carter on Fecundation in the two Volvoccs, 



Williamson*, and Cobn have been considered but one and the 

 same species, are specifically different. As, however, the opinions 

 of the two former in this respect are repeated by the latter, it 

 will be enough to cite here, in proof of this, the concluding 

 paragraph of the '' extract taken from Cohn's *' Observations on 

 the Organization and Reproduction of the Volvocinece-f/' which 

 runs as follows : — 



" He [Dr. F. Cohn] adds that there is no doubt that the 

 Spharosira Volvox of Ehrenberg is a monoecious Volvox globator ; 

 that his V. stellatus is the same V. globator filled with spinose 

 or stellose spores ; and that V. aureus only differs from the com- 

 mon Volvox by having accidentally smooth spores.'^ 



How the authors above mentioned arrived at such conclusions, 

 except from insufficient means of judging, I am ignorant ; for my 

 own observations lead me to the very opposite result, inasmuch 

 as the differences between Volvox globator and V. stellatus in 

 their adult forms, in the component parts of these forms, in 

 their course of development, in their mode of fecundation, and 

 in the form of their resting-spores, &c., appear to me to be so 

 great, that there is not the least room left for even doubt about 

 their being distinct species. But, as the reader will of course 

 not be content with bare assertion against such high authority, 

 I shall briefly describe these VolvocinecB under their respective 

 heads, leaving him to contrast the differences, and by aid of 

 the delineations of two which he will find arranged on opposite 

 sides of PI. I., thus form his own opinion of the truth of what I 

 have stated. 



Volvox globator, Ehr. PI. I. fig. 1. 



Adult form, — Spherical, or nearly so, consisting of three 

 generations or families, within one another, — that is, the parent 

 Volvox, containing generally eight daughters, in each of which 

 there are generally eight grand-daughters, all distinctly visible J. 

 Daughters confined to the posterior three-fourths of the sphere, 

 the anterior fourth being empty. Progressing with the empty 

 part forwards. Daughters rotating (this marks the adult form) 

 in their capsules respectively, which are fixed to the internal 

 periphery of the parent. Grand-daughters large and perceptible, 

 motionless, and fixed to the internal periphery of the daughters 

 respectively. Peripheral cells globular, biciliated, 57-1880ths 

 of an inch in diameter. 



* Quart. Journ. Microscop. Sc. vol. i. pp. 39, 56. 



t Annals, ser. 2. vol. xix. p. 187; translated from 'Comptes Rendus/ 

 Dec. 1, 1856, p. 1054. 



X Here I must use the terms " daughters" and " grand-daughters,'' and 

 omit that of " cell " as much as possible, for perspicuit3^ 



