TO A. HANCOCK, ESQ. 257 



months ago I had one rather careful inspection of the basal mem- 

 brane, and was much surprised not to be able to see the prehen- 

 sile antennas of the pupa, or any orifices for the cement-stuff; 

 yet from analogy I can hardly doubt that Clitia fixes itself like 

 all other Cirripedes, in the manner briefly explained by me to 

 the British Association. 



In the case of Coronula, Tubicinella, and Chelonobia, I have 

 fancied that the sinking was entirely or chiefly owing to the 

 growth of the surrounding parts of the animal to which the 

 Cirripedes were attached. I am much surprised about Clitia, 

 and it shows me that there is even in common Cirripedes some- 

 thing about their attachment which I do not understand at all. 

 I have seen, as I believe, that the cement could corrode through 

 the membrane of its own peduncle, but not act on the calcareous 

 scales supported by this membrane ; so that your fact of the 

 Modiola is still odder, and I hope you will allow me to quote it 

 from you. 



I have seen the larvse of most of the species of Anatifa, and 

 I think of A. vitrea,'^' but I have had either to dissect them out 

 of the egg and just after their escape, and never as yet when 

 naturally sent forth from the parent. In the state in which I 

 have seen them they certainly had not any 'process or pedicel,' 

 but exactly at the spot figured by you lies their mouth, which is 

 very slightly prominent, without any trophi, and leading into an 

 oesophagus running anteriorly and lost in cellular matter. If 

 you would let me have a few of these specimens I should be 

 very much obliged, and especially if you would give me any pre- 

 cise observations of your own on this ' pedicel, ' for I do not in 

 the least doubt that with all your experience in dissecting your 

 observations would be more trustworthy than my own. Goodsir 

 figures something like a masticating organ attached to base of 

 legs of larvae, which I could never see, and which, if such exist, 

 would be a strange coincidence with Limulus. 



No doubt you are aware that in all Cirripedes the larva from 

 the stage you have figured becomes (so called) bivalve, hexapod, 

 with prehensile antennae, binocular, etc. ; and when it attaches 



* = Lepas fascicularis. Mon. Cirr., Bay Soc, 1851, p. 92. 



