6o PEOCEEDINGS OF THE 



Certain yellow and green cells found in many animals are in 

 most cases symbiotic algae. The yellow cells (Fhilozon, Greddes ; 

 Zooxanthella, Lankester) are examples. They are common in 

 Eadiolaria, in Orhitolites amongst the Eeticularia, and in the 

 Infusorian Ceratium ; in the Hydroids, Velella and Cassiopeia. 

 They are also found in a particular variety of AntJiea cereus and 

 in Gorgonia verrucosa. 



Green cells, ZoocJilorella (Brandt), Ghlorella (Beyerinch), are 

 met with in Stentor, Hydra, Convoluta, &c. For purposes of 

 mutual advantage we find the alga Struvia delicatula associated 

 with a Halichondrine sponge ; TrentepoTilia spongopliila with the 

 sponge Epliydatia fluviatilis. Marchevetia spongioides (a red 

 alga) is similarly invested and modified in growth by a sponge. 



Time will only allow of my mentioning two other instances of 

 symbiosis between plants and animals. There is the well-known 

 instance of the plants Myrmecodia and Sydnophytuon, the lower 

 parts of whose stems are swollen and hollowed out into a series 

 of intercommunicating chambers which open externally, in the 

 first instance, near the roots, and afterwards by additional 

 openings at their sides ; there is thus formed a natural formi- 

 carium utilized by three species of ant, viz., FJieidole megacephala, 

 Cremastog aster deformis, and Iridomyrmex cordatus. These ants 

 defend the plant, and have entirely lost the power of making a 

 home for themselves. 



The bull's-horn acacia, Acacia cornigera, described by Belt, is 

 a most perfect instance of a plant modified in special relation to 

 the requirements of ants {Fseudomyrmex hicolor). Honey-glands 

 on the upper surface of the leaf -stalk supply the ants with food, 

 which is supplemented by little fruit-like bodies borne on the 

 extremities of the leaflets, whicb contain oil and granules of 

 aleurone, the hollow spines at the base of the leaf serving as a 

 home. It is impossible, within the limits of this Address, to 

 consider the numerous examples of symbiosis between animals, 

 of which hundreds of most interesting cases are known. 



The Address was illustrated by coloured chalk drawings. 



Dr. Eichard C. A. Prior then moved the following resolution, 

 viz. : — " That the thanks of the Society be given to the President 

 for his excellent Address, and that he be requested to allow it to 

 be printed." This, having been seconded by Mr. John Jenner 

 Weir, was carried unanimously. 



The obituaries of deceased Members were then laid before the 

 Meeting by the Senior Secretary. 



Obituabt Notices. 



Bt the death of Aethue Baeclat at Simla on the 2nd August 

 last, this Society has lost one of its youngest Members and most 

 zealous workers. He was born at Edinburgh, 3rd August, 1852, 



