TRANSACTIONS OF SECTION 0. 691 



FRIDAY, SEPTEMBER 11. 



After tlie President had delivered his Address (see p. 672), the following- Papers 

 were read : — 



1. The Bionomics of Convoluta roscoffensis, with special reference to its 

 Green Cells} By Frederick Keeble, M.A., and F. W. Gamble, D.Sc. 



Convoluta is remarkable for its green cells. Geddes showed that these cells 

 assimilate and form a reserve of starch. Y. Cxraft', failing to hud any trace of gut 

 or food in Convoluta, concluded that the animal is wholly dependent oil the green 

 cells for its food. Geddes' observation that Convoluta dies within two days if kept 

 in darkness is also taken as indicating the same dependence of the animal. Haber- 

 landt investigated the histology of the green cells and discussed their origin 

 without coming to any well-founded conclusions, leaving it uncertain whether the 

 green cells enter the animal from without or arise within it. 



Our researches deal with the relation between green cell and animal and with 

 the question of the origin of the green cell. We lind that Convoluta feeds vora- 

 ciously, taking up diatoms, algfe, spores of various kinds, litmus, indigo, lamp-black, 

 and potato-starch ; that Convoluta lives for three weeks in dai-kness without any 

 especial precautions ; and that the stoi'e of starch is reduced very slowly, not dis- 

 appearing until after eight days. From these conclusions it would appear that 

 Convoluta is less completely dependent on the green cell than was supposed. 

 Nevertheless under certain circumstances the animal digests its own green cells. 



With respect to the origin of the green cells Georgevitch has shown that the 

 larvae of Convoluta are colourless, and that they die in two daj'S if kept in filtered 

 water. We show that the earliest stage of the green cell is a colourless or almost 

 colourless cell ; that colourless larvpe may be kept in filtered water for upwards of 

 a month; and that when sea-water is added infection follows, whereas when main- 

 tained with sufficient precautions in filtered sea-water no infection occurs. We 

 conclude that the green cell is an alga, a stage in the life-history of an oi'ganism 

 widely distributed in sea-water; that it makes its way into the body of Convoluta, 

 multiplies there, and almost invariably dies with its host. From the characters of 

 the green cell we conclude that it is a hypertrophied zoospore. 



Questions of considerable interest still remain, as in all cases of symbiosis. For 

 example, the origin of the proteid food material required by both animal and plant ; 

 the question as to whether the animal may avail itself of the carbohydrates of the 

 green cell otherwise than by destroying that cell. 



2. Note on the Skull of Grampus gvisews found on the Coast near Galway, 

 By Professor Richard J. Anderson, M.D. 



A grampus of considerable size got stranded on the coast near Galway a few 

 years ago. The cai-cass was lost, but the skull was found last winter ; and as this 

 cetacean is far from common in Ireland, a few points with reference to the structure 

 of this fragment may be noted. The skull is much smaller than that of Globio- 

 cephalus melas, and much less massive, and the sockets for the teeth in the upper 

 jaw are small and inconspicuous. It is evident that the sockets have been filling 

 up for years. The number of teeth in Gratnpiis (/riseus varies from two to six in 

 the lower jaw. They are more numerous in the young mature than in the old, and 

 the upper jaw seems to be edentulous ; the teeth are deciduous. A young skull 

 found on the beach, some time ago, which belonged to a small specimen washed 

 ashore, was considered to be that of a Grampus (/riaeus (Rissoatms) by Professor 

 D'Arcy Thompson, in all probability the ofispring of the specimen here noted. 

 The length of the animal was proloably about 12 feet. This size corresponds 

 to that of Rissoanus. This is borne out by the dental groove, traces of which, as 



' Will appear in the Proc. Roy. Sac, London. 



T y3 



