Royal Physical Society. 455 



from the side of which buds a single ovarian sac inclosed 

 within a layer of the ectoderm (b) of the polyp. The endo- 

 derm of the ovary (c) is branched or lobed, and is moulded, as 

 it were, on and between the ova which lie between it and the 

 ectoderm of tlte ovary (d). As development proceeds, the ova- 

 rian sac (its endodermic lobes having been previously ab- 

 sorbed) rises up to, and issues from, the top of the cell (fig. 3), 

 and becomes surrounded by a thick gelatinous mass, secreted 

 from the surface of the ectoderm. The ectoderm of the ovary 

 now bursts, leaving the ova in the gelatinous marsupium, 

 where, as in Sertularia pumila, &c, they become developed 

 into ciliated larvse. 



The male cell resembles' the female cell. Instead of an 

 ovary, a spermatic sac buds from the reproductive polyp. At 

 first a transparent gelatinous plasma is secreted between the 

 branched endoderm and the ectoderm, as at (a) fig. 1. In 

 this plasma the spermatic cells, and subsequently spermatozoa, 

 are developed. Meantime, the sperm-sac rises to the top of the 

 cell, is extruded (6), and bursts. 



IV. (1,) A few remarks on Lamellaria tentaculata, and its Nidiftcation, 

 fyc, as observed at Wick. By Charles W. Peach, Esq. 



In March 1854 I met with Lamellaria tentaculata in 

 some abundance, under stones at the back of the South pier 

 of the harbour of Wick. I had seen one or two there before. 

 On finding them so plentiful, I guessed their errand, and set 

 myself to observe their movements, and succeeded in obtain- 

 ing the clue, more especially after I had kept some in a vase 

 in my house for some time, — they were in-shore for nidifica- 

 tion; with these I found that the rocks were covered with 

 patches of glairy jelly-like matter, which I thought had been 

 deposited by the Lamellaria ; in a week or two a great change 

 had taken place in it, both in colour and consistence, and I 

 saw that it was filled with dark spots, after careful examina- 

 tion it proved to be Leptoclinum punctatum, of Forbes and 

 Hanley's " British Mollusca," vol. i., page 18. My reason 

 for suspecting that it belonged to the Lamellaria arose from 

 the latter being so much on this matter. I have been thus 

 particular in referring to the Leptoclinum, for it will be seen 



vol. i. 2 u 



