Royal Sociehj. 407 



PROCEEDINGS OF LEARNED SOCIETIES. 



ROYAL SOCIETY. 



February 21, 1861. — Major-General Sabine, Treasurer and Vice- 

 President, in tlic Chair. 



" Notes on the Generative Organs, and on the Formation of the 

 Egg, in the Annulosa " (Part I.), by John Lubbock, Esq., F.R.S. 



In the present paper I have communicated some observations on 

 the Myriapoda, on Petrobius, and on certain Arachnida. Among 

 the former I have examined species belonging to the genera Glomeris, 

 lulus, Polydesmus, Lithobius, Cryptops, Geophilus, and Arthrono- 

 malus. Through the labours of Brandt, Fabre, Newport, Stein, 

 Treviranus, and other eminent naturalists, we are tolerably well 

 acquainted with the anatomy of the generative organs in the 

 ISIyriapods ; but these observers have occupied themselves principally 

 with the arrangement and forms of the organs, and have not paid much 

 attention to the different stages of egg-development, nor to the rela- 

 tion in which the young egg stands to the surrounding tissues. This 

 relation is indeed very curious, and seems to have been generally 

 misunderstood. It is well known that there are in the Myriapods 

 no long egg-tubes, as in most insects, but that each egg arises in a 

 separate follicle. It was, however, natural to suppose that this follicle 

 held the same position with reference to the ovary as the very similar 

 egg-follicles of certain insects, as, for instance, of Coccus. This, 

 however, is by no means the case. If we compare the ovary and 

 egg-follicle of Coccus with the ovary and egg-follicle in Glomeris, we 

 shall see that the egg-follicle is very much alike in both cases, — the 

 shape of the follicle, the Purkinjean vesicle, and the vitelligenous cells 

 being very similar ; but whereas in Coccus and in all insects the egg- 

 follicle projects /ro»« the ovary, in Glomeris and the other Myriapods, 

 so far as my observations go, the follicle projects into the ovary. If, 

 therefore, we consider the ovary as consisting of an outer membrane 

 {ind an inner epithelial layer, it would appear that while the egg in the 

 Myriapods arises between these two layers, in the insects it originates 

 on the inner side of both. 



This diiference appears to me to be very important, and, as will be 

 mentioned under the head of lulus, escaped the attention of our great 

 anatomist Newport, whereby he was led to give an erroneous descrip- 

 tion of the ovary of that genus. I have chosen to compare Glomeris 

 with Coccus, because the vitelligenous cells make the resemblance, 

 and, at the same time, the difference between these two genera more 

 striking. If we, however, compare with them the ovary of Fhalati' 

 gium, we shall see not only that the vitelligenous cells are absent, but 

 that the egg-follicle differs equally from that of the insect on the one 

 hand, and that of the Myriapod on the other. The egg- follicle projects 

 from the ovary as in Coccus, &c. ; but, on the other hand, the Purkinjean 

 vesicle lies on the outer side of the epithelial layer, as in Glomeris, 

 and in consequence the egg-follicle, which in Coccus consists of both 

 the ovarian membranes (so far as the epithelial layer can be called a 



