631 



A paper by George Busk, Esq., entitled ' Some Observations on 

 the Structure and Development of Volvox globator, and some allied 

 Unicellular Plants,' was read. Mr. Busk stated that his observations 

 had been chiefly made on Volvox globator, V. aureus, V. stellatus, 

 and Sphaerosira Volvox of Ehrenberg. These he believed to be all 

 different forms of the same organism. He called attention to the 

 structure of these objects, and more especially as regarded some 

 points alluded to by Prof. Williamson in a paper recently published 

 by that gentleman on that subject ; and while in some respects he 

 expressed a diff"erent opinion from Mr. Williamson, he fully agreed 

 with him that they were truly of vegetable origin, and not animals. 

 This he considered as proved, both by their structure and their che- 

 mical composition. Thus, on testing their tissues with iodine and 

 sulphuric acid he had discovered in them both cellulose and starch. 

 The analogies of their development with that of Protococcus nivalis 

 and of P. viridis were very strong, as also with the supposed animal- 

 cules called Euglenia viridis. The author expressed his belief that 

 the whole of the Monadinae, the Cryptomonadinae, and the Volvoci- 

 nia of Ehrenberg belonged to the vegetable rather than to the animal 

 kingdom. 



A second paper, by Mr. Mummery, of Dover, ' On the Develop- 

 ment of the Young in Tubularia indivisa,' was read. The author, 

 taking advantage of his residence on the sea-shore, where these zoo- 

 phytes abound, has for a considerable period attentively watched the 

 development of the ova ; and the results of his observations form the 

 subject of the present paper. The various changes in the ovum, from 

 its first development to its arrival at perfection, were minutely de- 

 scribed ; and when the creature is liberated its future basal end ap- 

 pears first. It emerges slowly, withdrawing its tentacles in succession 

 until it sets itself at liberty. In this state it is not fixed, but free, 

 and may be seen crawling slowly upon the bottom of the vessel con- 

 taining it, and elevating itself on the extremities of its eight tentacles. 

 After a period of time varying fiom one to four days the animal, which 

 in its free condition has never been remarkable for activity, having 

 selected a suitable stone, or the surface of an old polypidom, reverses 

 its position, and attaches itself, with the mouth upwards, by the op- 

 posite extremity, and soon increases in size, and attains its usual form 

 and characters, never removing from its place after having once rooted 

 itself.— J. IV. 



