ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 351 



duction has been observed ; but he thinks it possible that it may have 

 multiplied in the autumn by division. 



Mr. C. S. Minot thinks * that the animal bears a strong resem- 

 blance to a sponge-larva. 



Chlorophyll of Animals."]" — In the introduction to this very im- 

 portant paper on the morphological and physiological significance of 

 chlorophyll in animals, K. Brandt resumes the results of his earlier 

 investigations, in which he set himself to demonstrate that chlo- 

 rophyll formed by animals is never found ; that, where present, it is 

 due to the presence of unicellular algte ; and that the animal hosts 

 may be nourished owing to the assimilative power of these alg^. 



Commencing with an account of the " yellow-cells," he gives a 

 list of the animals in which they have been observed — Foraminifera, 

 Eadiolaria, Flagellata, Ciliata, Sponges, all three groups of Coelen- 

 terata, two Echinoderms, one Bryozoon, three Turbellaria, and one 

 Annelid. The algal nature of the yellow-cells is next discussed, the 

 views of Geddes criticized closely, and the algal nature upheld ; the 

 organization of these bodies is discussed in detail, and the characters 

 of the different forms found in various animals described and 

 criticized. 



This section of the essay concludes with a discussion of the 

 question, to what group of alg^e these yellow-cells belong, and the 

 result is arrived at that they are the resting-stages of various marine 

 algfe, and especially of the Melanophycese. The further detailed 

 result may be left to professed physiologists. 



After some account of the pseudo-chlorophyll bodies, the author 

 passes to the symbiosis of animals and algsB ; animals may live inde- 

 pendently of alg^, and alg^ of animals, but the Eadiolaria appear to 

 be very dependent on their guests. After having convinced himself 

 of the fact that yellow-cells can nourish their animal hosts, Dr. Brandt 

 turned to the mode in which this is effected ; in the Collozoa 

 he found, after treatment with iodine, numerous small granules of 

 starch in the protoplasm of the animal. As these were specially 

 numerous on the outer surface of the yellow-cells and in the neigh- 

 bourhood of completely intact yellow-cells, and agreed in all their 

 important characters with those found in the cells, they may fairly be 

 regarded as assimilative products of the yellow-cells that have become 

 free. From these observations it is clear that the assimilation pro- 

 ducts of the living yellow-cells may partly serve the animals, and it 

 is possible that in animals the assimilative processes of the alga go on 

 more actively, inasmuch as they are there more richly provided with 

 carbonic acid than they are when free in the water. In fine, the 

 author has no doubt that the guests do provide starch for their hosts. 



Some experiments have been made on the production of oxygen 

 which have led to the following conclusions : — Alga- containing 

 Actiniae, if brought from diffused into direct sunlight, exhibit no 

 irritation, if means are taken to prevent a rise in temperature. If the 



* Science, i. (1883) p. 305. 



t MT. Zool. Stat. Neapel, iv. (1883) pp. 191-302 (2 pis.). 



