592 SUMMARY OF CURRENT RESEARCHES RELATING TO 



cell in Co)ivoluta faradom, and publish their results in the present 

 paper, which is divided into the following sections : (1) Introduction ; 

 (2) proof of the origin of the green cells by infection ; (S) the isola- 

 lation of the infecting organism and the synthesis of the green Coii- 

 voluta ; (4) the life-history of the infecting organism ; (5) the normal 

 course of infection ; (6) the significance and the consequences of the 

 association of animal and green cell ; (7) general summary. The infect- 

 ing organism of Convoluta is found to be an alga belonging to the 

 Chlamydomonadeae, which in its free stage bears four equal flagella 

 and possesses the general characters of members of this family. It 

 may possibly be a species of Carteria. The active cells are of two sizes, 

 but neither large nor small cells appear to be obligate gametes. The 

 organism is capable of a' saprophytic as well as of a holophytic 

 existence ; in the former state it may be colourless. The active cells 

 are attracted chemotactically to egg-capsules oi Convoluta. They settle 

 down and undergo active vegetative division in the capsules, and are 

 finally liberated as a swarm of four-flagellated active cells. The re- 

 lation between green cell and animal changes with their development, 

 passing from a symbiotic relation to one in which the animal is para- 

 sitic on the algal cells. The consequences of the association, so far as 

 the algai is concerned are, hypertrophy, nuclear degeneration, premature 

 senescence, and death. The results of various experiments are shown 

 by the help of tables. The paper is illustrated by two plates. 



Unicellular Algae and Alcyonaria.* — C. Gravier discusses the uni- 

 cellular alg^e which are found plentifully in all parts exposed to the 

 light of certain Alcyonarias and coralline Polyps. He distinguishes 

 two periods in the life of these organisms : the first, during which 

 they are parasitic, and live in the interior of the mesoderm ; the second, 

 during which they provide for their own nourishment, and contribute 

 at the same time to the support of the colony in which they live. In 

 the first state they have the form of a sphere, about 8/x in diameter, with 

 hyaHue protoplasm, and possessing one, rarely two, refriugent bodies, 

 the volume of which slightly exceeds that of the nucleus. They form 

 an almost continuous covering near to the upper surface, and penetrate 

 also into the endoderm. The second form of these unicellular algse is 

 quite different. They are less regular, generally elongate, and larger 

 than in the first state, measuring along their greatest axis 18 /x.. They 

 are all situated in the mesoderm, where they form dense irregular ranks, 

 frequently anastomosing. They multiply by bipartition, 



Algse of North Devon. t — C. E. Larter publishes a list of 137 algse 

 gathered by himself, E. M. Holmes, and others, in the botanical districts 

 of Braunton and Sherwill, in North Devon. Among them is Callymenia 

 Larteri Holmes, a new species collected at Combemartin by Larter in 

 1906, and without description here, but subsequently described and 

 figured as C. Larterm in Journ. of Bot., xlv. (1907) p. 85. Notes on 

 Stenogramme interrupta and Nitophyllum Gmelini are added. 



* C.R. Acad. Sci. Paris, xxv. (1907) pp. 1462-4. 



t Rep. Trans. Devon. Assoc, xxxviii. (1906) pp. 286-93. 



