REPORT ON ZOOLOGY, 239 



siliceous tubular spicula, ramified internal canals, tubular papillae, 

 regular currents, and the distribution of its ova." In another, 

 published the same year in the same journal, he has detailed 

 some observations on the spontaneous motions of the ova of 

 several species of zoophytes, a motion which, though long since 

 observed by Ellis in the case of the Campanidaria dichotoma. 

 Lam., scarcely seems to have attracted notice afterwards, not- 

 withstanding its importance as connected with the mode of 

 generation in tiiese animals. In 1827, Dr- Grant also published 

 two papers in iheEdinb. Journ. of Science, one* on the structure 

 and mode of generation of the Virgularia mirahilis and Penna- 

 tula phosphorea, the otherf on the generation of the Lohidaria 

 digitata. A supplement to his first memoir appeared in the 

 same joui-nalj in 1829. 



About the same time as that when Dr. Grant was engaged 

 with these researches, two or three observers in France were 

 busied in a similar investigation, as well of the Sponges as of 

 some of the freshwater gelatinous Polypi of Cuvier's second 

 order. Raspail and Robineau-Desvoidy first read a memoir to the 

 Royal Academy of Sciences in 1827 § on the ^/cyo?ieZ/a of Lamarck. 

 Their object was to elucidate the structure of this ill-understood 

 zoophyte, and more especially to show that the supposed Po/5//9^ 

 seen in it by Lamarck were only parasites, probably belonging 

 to the genus Nais, the tubes of the Polypier being naturally im- 

 perforate. This opinion was, however, retracted by Raspail in 

 a second and very elaborate memoir on this zoophyte read the 

 same year||, in which he acknowledged the existence of the Po- 

 lypi, but sought to prove by a course of detailed observations that 

 this genus was not distinct from Cristatella or Plumatella ; that 

 in fact these three genera, as well as Difflugia of Lamarck, were 

 one and the same animal in different stages of development^. Ras- 

 pail also made several observations on the structure of Sponges, 

 in some respects analogous to those by Dr. Grant. In a me- 

 moir, likewise read in 1827 and published the year following**, 

 he gave the results of a microscopic examination into the struc- 

 ture of the Spongilla friahilis, many of which results, however, 

 differed very materially from those arrived at by our own coun- 

 tryman. Part of his object was to point out an analogy be- 



* vol. vii. p. 332. f vol. viii. p. 104. J vol. x. p. 350. 



§ Cuv., Anal, den Trav., 1827. 



II This second memoir was subsequently published in the Mem. de la Soc. 

 d Hist. Nat. de Paris (torn. iv. p. 75). 



^ Further researches seem necessary in order to establish beyond doubt the 

 identity of the above genera. The opinion of Raspail on this point has not 

 been universally adopted. 



*• Mem. de la Soc. d'llist. Nat. de Par., torn. iv. p. 201. 



