400 THE OPISTHOBIUNCHIATE 



colour in this group of animalsj extending tlie observations of Giard 

 upon protective colouration, and supporting Wallace's view that tlie 

 colours of Solids are generally " vs^arning colours as a sign of in- 

 edibility/' In conjunction with Mr. Clubb^ he has also published 

 an account of a number of experiments designed for the verification 

 of these views. Having been myself occupied from time to time in 

 similar experiments, a few of the decisive results were communicated 

 to Mr. Poulton, who has inserted them in his recent work on The 

 Colours of Animals (Int. Sci. Series, London, 1890, pp. 199, 200). 

 I hope soon to give an account of the results of other experiments. 



In this paper I have taken the opportunity of correcting some 

 mistakes of classification and nomenclature which had not been 

 avoided in my report on the Nudibranchiata. 



It is a pleasant task to express my sincere thanks to those wh© 

 have generously helped me in the investigations here described, 

 and particularly with regard to Aplysia. I am especially indebted 

 to Dr. Norman and to Mr. A. R. Hunt. 



OPISTHOBRANCHIATA. 



Sub-order l.-TECTIBRANCHIATA 



(=OPISTHOBIlANCHIA PALLIATA, Lankester). 



A. CEPHALASPIDEA. 



i^am*7i/— SCAPHANDRID^. 



1. Scaphander, Montfort. 



1. Scaphander lignarius, Linnseus. 



This species is frequently obtained by trawlers on the Eddystone 

 trawling-grounds ; it does not live in the Sound, but has been 

 taken off Penlee Point. 



jPami7;/— BULLID^. 

 2. Haminea, Leach. 



2. Haminea hydatis, Linnaeus. 



Several large specimens were di^edged in the estuary of the river 



Rep. Brit. Assoc, 1889, Section D ; and Quart. Journ, Micr. Sci., xxxi. Prof. Herdman 

 kindly sent me copies of these papers, which, though containing views similar to some 

 expressed in my previous Report, were written for the most part before its publication. 



^ Herdman and Clubb, Third Report on Nudibranchiata of L.M.B.C. District, Trans. 

 Liverpool Biol. Soc, iv, 1890, pp. 150—163 ; and Nature, June 26th, 1890, pp. 201—203. 



