CRYPTOPHIALUS M1NUTUS. 567 



depressed, with its superior edge prolonged a little upwards ; 

 by this side, the animal is attached to the cavity in the shell, 

 within which it is lodged. There is here no distinction 

 between a peduncle and capitulum, that is between the 

 lower or anterior, and the upper or posterior end of the 

 animal, as seen externally. The small orifice is toothed and 

 hairy : it is coloured purple, as is likewise the projecting 

 labrum ; the rest of the animal being tinted only by the 

 muscles and internal parts seen through the outer integu- 

 ments. The largest specimen (fig. 2) which I have measured 

 did not quite attain the length of one tenth of an inch. 

 This cirripede inhabits, in vast numbers, the shells of the 

 living Concholepas Peruviana, amongst the Chonos islands ; 

 the whole outside of the shell being sometimes completely 

 drilled by its cavities, almost touching each other, as hap- 

 pens in the case of Alcippe with the shells of Buccinum. 

 The oval aperture leading into the shell-cavity, in full-sized 

 specimens, is between ^ of an inch in length : it is gene- 

 rally surrounded by a narrow, internal, calcareous rim, 

 which apparently has the same inorganic origin, as in Alcippe. 

 The toothed orifice of the carapace leading into the sack, 

 fills up the orifice of the shell-cavity ; but it can be volun- 

 tarily withdrawn a little : when opened, and the animal is 

 in action, the lancet-formed, moveable crest of the labrum^ 

 and the abdominal cirri, are exserted. 



Integuments. — The external membrane is colourless, thin, 

 but strong ; it is studded with minute bifid, trificl, and 

 quadrifid points of hard chitine, which are the agents of 

 excavation : they are directed upwards, except towards the 

 lower end, where they are directed from the disc or surface of 

 attachment. These points beneath the orifice, and on each 

 side close along the lateral bar, are larger than elsewhere. 

 There are no points on the disc or surface of attachment, which 

 is formed of somewmat thickened, yellowish membrane, and 

 is not moulted, like the rest of the external membrane, but 

 is formed of successive layers extending beyond each other ; 

 the lines of growth, however, being obscure, and only occa- 

 sionally distinguishable. The disc is oval, not extending 

 to the lower end of the animal, and with the upper edge thin- 

 ning out and produced upwards (fig. 1). The animal, during 



