TO A. HANCOCK, ESQ. 255 



Sciences, 1st series, 1844, p. 192-4.' Secondly, will you be so 

 kind as to tell me on what being (for I cannot read the word) 

 your specimen of the Ihla is attached. And thirdly, whether 

 you had any motive for calling your Cirripede 'Alcippe,' as per- 

 haps I will change my long name of Arthrobalanus for a shorter 

 one. Any time will do for an answer. 



With respect to Lithotrya. The shells have relation to diam- 

 eter of hole, but the shell-part of full-grown ones, / believe, 

 project beyond their hole. This is hard to know, as peduncle 

 shrinks much from drying. Holes are bored in all directions. 

 The animal often rises a quarter of an inch in its hole from 

 thickness of cup. Yery young specimens have cups, I believe at 

 earliest period. I cannot describe the whole process of fixing in 

 letter, but I must think it quite impossible that any Cirripede 

 can sink its basis in any object. I have thought that the larva 

 of Lithotrya instinctively (and this not wonderful) creeps into 

 the crevices of the coral-rocks to that depth, from which it can 

 when nearly full-grown freely reach the surface ; in the interval 

 I believe it feeds on Infusoria in the water circulating in the 

 crevices. I once thought that the larva of Arthrobalanus might 

 have bored its hole with its prehensile antennae, but I cannot 

 now believe this. But there is another view or conjecture, which 

 is perhaps the most probable, viz., that the larva (in second 

 stage) boring a minute hole by an acid secreted from some gland, 

 and through some duct and orifice in the prehensile antennse 

 (alluded to by me in Athenceum), by which afterwards the cement- 

 stuff is poured out. This view would perfectly harmonise with 

 the facts, of which I cannot doubt, that the Cirripede after meta- 

 morphosis can never alter its point of attachment; and secondly, 

 the apparatus of minute points for enlarging its cavity in Litho- 

 trya, Arthrobalanus, and Alcippe, is equally applicable. 



But I shall utterly weary you with this discussion. Tour 

 statements about cavities of Alcippe make me doubt my view of 

 the larva creeping into already existing cavities. 

 "With my sincerest thanks, 



Yours very faithfully, 



C. Daewdt. 



