HORNELL— THE PRESENCE OF SYMBIOTIC ALG^ IN MELIBE 145 



is very minutely serrulate. The ramifications of the liver extend to the extreme edges 

 of the wings and tip of the tail and are very distinctly visible from the outside. 



As pointed out in my paper referred to above, there is much confusion in the 

 nomenclature of the tropical ElysiidcB, but Kelaart's names appear to be the earliest 

 and grandifolia should be kept as the specific designation of a large species with a 

 pointed tail and typically of a green colour with two borders, yellow and black, which, 

 however, are not developed in all specimens. 



A NOTE ON THE PRESENCE OF SYMBIOTIC ALG^ 

 IN THE INTEGUMENTS OF NUDIBRANCHS OF THE GENUS MELIBE, 



By JAMES HORNELL. 



During the Ceylon pearl fishery of 1905, when making my daily visit of 

 inspection to the boats at work, it was my habit occasionally to board one or 

 more to note the progress and conduct of the diving operations. One day in 

 February when aboard a boat fishing on the South Moderagam Par in six 

 fathoms, my eyes fell upon a handful of flaccid brown masses in a diver's net just 

 drawn up. My first thought was that they pertained to some species of Aplysia, 

 several of which are extremely abundant at times on the pearl banks : I was about 

 to pass them as of no importance when a something unfamihar in their appearance 

 caused me to reach forward to take possession. But a diver a second before I 

 could pick them up flung the greater part back into the sea and I had but four 

 left. 



These I examined on return to my quarters, and then found them of greater 

 interest than I had imagined. The four masses were practically identical in form, 

 colouring, and size ; none showed any trace of alimentary canal or of any orifice 

 whatever, but each showed a disc-shaped place of attachment, 5 mm. in diameter, 

 on one surface. Each mass was laterally compressed, stout and fairly thick towards 

 the disc of attachment, thence narrowing gradually to a thin crest-like ridge upon 

 the upper margin, and in general form closely resembling the crested pneumatophor 

 of Physalia. In vertical transverse section it was distinctly pyriform in outline. 

 The o-round coloration was of two shades of brown, irregularly distributed, and 

 flecked here and there with small irregular patches of grey. 



When I handled the masses first, the surfaces were covered with closely-set, 

 low wart-like papillse irregularly distributed, at some places more or less aggregated 

 in fairly densely-set groups, at others rather widely separated from one another. 

 After immersion in water for some minutes, the appearance underwent a considerable 



