844 Proceedings of the Royal Irish Academy. 



of a pale yellowisli flesh-colour, another (that from Valencia) 

 was of a rich golden brown colour, and the third of redder hue, 

 closely resembling that of some red Algse^ obtained in the 

 same haul of the dredge. The colour in each case was due to 

 minute scattered granules in the integument, hardly visible 

 except under the microscope, and interfering very little with 

 the transparency of the tissues. The only opaque colouring 

 material present was confined to the deep yellow tips of the 

 velar processes and of the papillae of the rhinophoral sheaths 

 and pleuropodium. Apart from their yellow tips, the ground 

 colour of the papillse was deeper than that of the rest of 

 the dorsal surface, while the foot was paler than the 

 latter. 



The colouring of the specimens of Thompson and Norman 

 differed slightly in detail, but not to an important degree, from 

 any of my specimens. They certainly show no approach 

 towards L. marmorahis, and they are described as "pellucid" 

 and "very transparent" respectively. It is very difficult, not 

 to say impossible, to believe that these large individuals were 

 ever pigmented like Z. marmorata when young. I have, 

 moreover, found one individual, only 9 mm. long (adhering to 

 Cellaria, trawled in the English Channel off Plymouth), which 

 was undoubtedly a young example of the large form. I had no 

 living specimens of L. marmoratus at the time with which to 

 compare it, but it appeared to me to be proportionally wider, and 

 to have the pleuropodium more developed and foliaceous than 

 in the last-named. This may have been a question of exten- 

 sion, however. The outer tissues were almost colourless, the 

 dorsal surface having a faint orange tinge from the presence of 

 a few scattered microscopic specks of dark red and reddish 

 orange ; and moderately transparent, so that the pale fawn- 

 coloured digestive organs showed through. The velar pro- 

 cesses and the papillae of the rhinophoral sheaths and pleuro- 

 podium were tipped with bright orange yellow, as in the large 

 examples. I should judge one of Garstang's specimens^ 

 (15 mm. long) dredged south of the Plymouth Mewstone, to 

 belong to this form also. 



1 Scinaia purcellata and Belesseria sanguinea. 



- That described first {loc. cit., p. 186). The other two specimens from the same 

 locality (described p. 187) were obviously L. viarmoratus. 



