PISSURELLID^. 123 



has a septum across the hollow ; and others again, like our 

 species, have the spiral plate. 



C. Sinensis lives on rocks or stones ; it has eyes on its 

 tentacula, which are short and rather pointed ; the spawn 

 is laid on the stones, wrapped up in bundles of fringed mem- 

 brane. The fry show a regularly spiral shell, and it is only 

 in growing that the sides become expanded so as to form a 

 limpet. ^^Mr. Alder has observed the Calyptrceci to carry 

 and hatch its spawn under the neck, in front of the foot." 



FISSURELLID-ffi. 



The few representatives of this family of '^ Key-hole Lim- 

 pets '^ in British seas will be best described under their re- 

 spective genera. 



I. FissuRELLA reticulata is like an oval cross-barred Kmpet, 



with a hole at the top of the shell for the anal tube. 

 On the mantle there is a row of little cirrhi, one corre- 

 sponding with each rib in the shell. Another row of 

 cirrhi surrounds the foot. The eyes are placed on little 

 knobs at the base of the tentacles. 



II. PuNCTURELLA Noachiua has a hole in the shell, not at, 



but behind the apex, through which the anal siphon 

 prominently protrudes ; the shell is small, white, very 



