132 LIVEEPOOL BIOLOGICAL SOCIETY. 



This report is divided into three parts : — (1) the system- 

 atic account of the species, (2) some remarks upon the 

 epipodial nature of the cerata, and (3) an account of the 

 experiments with fishes. The usual tabular view of the 

 distribution of the recorded species throughout the district, 

 brought up to date, will be found on p. 146. 



Part I. Systematic Account of the Species. 



NUDIBRANCHIATA. 



A. PYGOBKANCHIA ( == HOLOHEPATICA) . 

 Family DoRiD^.* 



Archidoris tuherculata, Cuvier. 



We have several times lately found this common species 

 lying in hollows of large sponges {[lalklwndria jfauicea), 

 the Nudibranch being in such cases very completely hidden 

 from observation. Garstang f has recently noticed this 

 protective resemblance in specimens found at Plymouth, 

 and Giard I has referred to it in discussing the Nudi- 

 branchs at Wimereux, on the coast of Normandy. In 

 1888 we described § a remarkable specimen which was 

 so coloured as to resemble exactly the lining of the rock- 

 pool in which it lived. 

 Lamellidoris hilamellata, Linnaeus. 



This is the commonest species of Dorid in the Mersey, 

 and although richly coloured with yellow and brown, so 



* We consider the form " Doridre " preferable to " Dorididre " as it avoids 

 confusion with the family Doridiidte formed for the genus Duridium. 



tJour. Mar. Biol. Assoc, vol. i. no. 2, p. 174. 



+ Bull. Sci. de la France, &c., t. xix., p. 492. Giard had also pointed out 

 some years before (Arch. Zool. 6xp6r., t. ii., 1873, p. 487) that this and 

 a few other species sometimes resemble the conn)ound ascidians upon which 

 they live. 



§Proc. P>iol. Soc, L'pool, vol. iii., p. 13. 



