NUDIBEANCHIATA OF THE L.M.B.C. DISTRICT. 133 



as to be a striking object in a white dish or a vessel of 

 clear water, it is quite inconspicuous on the dark purple- 

 brown rocks spotted with patches of adhering mud, sand, 

 small algae and zoophytes found in this neighbourhood. 

 We were much impressed with this on a recent visit 

 (March, 1890) to Hilbre Island when we found that a reef 

 of rock we were exploring had a number of specimens of 

 this species scattered over it w^iich were not at first 

 noticed because of the perfect manner in which their 

 colours blended with those of the surroundinsfs.* 

 LamelUdoris proxima, Aid. and Hanc. 



We have taken this again at Puffin Island and Hilbre 

 Island, and Dr. Hanitsch found it at Port Erin, Isle of 

 Man, in April, 1890. 



AcantJiodoris p'dosa, 0. F. Miiller. 



Found again at Hilbre Island, March, 1890 — colour dark 

 grey. Transverse sections of this species bring out very 

 clearly that the large papillae on the dorsal surface are 

 much more prominent on the sides than along the middle 

 line of the back (PL VI. fig. 5). 



Family Polycerid^. 

 Goniodorls nodosa, Montagu. 



Found at Port Erin, Isle of Man, in April, 1890, by Dr. 

 Hanitsch. We have made use of specimens of this species 

 for an enquiry into the condition of the epipodial ridges 

 (PL VI. fig. 6) which will be discussed below. 



Pohjcera quadrilineata, 0. F. Miiller. 



Dr. Hanitsch obtained some specimens at Port Erin, 

 Isle of Man, in April, 1890. We have found this species 

 an important transition form, in the condition of the 



^ 111 this connection see the experiments on fishes given on p. 152, and the 

 remarks on colour on p. 162. 



