120 



TRANSACTIONS LIVERPOOL 1UOLOGICAL SOCIETY 



from the egg dart about the tank from darker to lighter 

 coloured parts. 



Some Gastropods, such as the sea-hare {Aplysia 

 ■punctata), found by dredging in the bay, have very small 

 shells, which do not cover the body. 



The common limpet [Patella vulgata) is frequent on 

 the shore, and the beautiful transparent brown Helcion, 

 with its radiating lines of delicate turquoise blue, is found 

 at low tide on the blades and stems of the oar-weed. 



Fig. XXIV. — Nudibranchs (slightly enlarged. 



Reports upon the various groups of shell-bearing 

 Mollusca, by Mr. R. D. Darbishire, Mr. F. Archer, Dr. 

 W. E. Hoyle and Mr. A. Leicester will be found in the 

 volumes of our " Fauna." 



There is one set of Molluscs related to the ordinary 

 univalve Gastropods which have lost their shells. These 

 are the Nudibranchs or sea-slugs, four common kinds of 

 which are shown in fig. XXIV. Xo. 1 is the large yellow 



