72 G SUMMARY OF CURRENT RESEARCHES RELATING TO 



cells. Amongst the conclusions arrived at are, that Convoluta has not 

 lost its power of independent nutrition. It feeds voraciously, and obtains 

 little if any nourishment from the reserves of its green cells ; these are 

 not symbiotic, they derive food from the animal and appear to be 

 facultative parasites ; the green cells are the result of infection by 

 colourless cells, which are taken up in company with other organisms 

 and are carried by wandering cells to the periphery, where the majority 

 become green. It is suggested that the colourless cell is a saprophytic 

 stage in the life-history of the green cell. 



Convoluta lives in a film of water, and is neither a sub-aerial nor 

 a marine animal. The stations occupied are remarkably constant, and 

 show diurnal and fortnightly variations in the size of the colonies, the 

 former being tidal, and the latter due to periodicity of reproductive 

 phenomena. Interesting tropisms are also described. 



Two Remarkable Sporocysts from Mytilus latus.* — W. A. Haswell 

 describes (a) the sporocysts of an Echinostomum very abundant in about 

 10 p.c. of the mussels examined. They multiply not only by budding, 

 or rather binary fission, but also, though comparatively rarely, by a 

 process corresponding to that by which in many, if not most sporocysts 

 rediie are formed. One of the remarkable features is the occurrence of 

 pigment in the germinal epithelium ; another, though it may have been 

 overlooked in other cases, is the giving off of colourless nutritive globules 

 by the germinal epithelium. The structure and development of the 

 cercariae is described, (b) Haswell also found the sporocysts and 

 cercarife of a species of G aster ostomum — the cercariae having the 

 remarkable form known as Bucephalus v. Baer. 



Nemerteans of Norway.f — R. C. Punnett raises the list from 15 to 

 84 species. Between 40 and 50 Nemerteans are known from British 

 coasts, and of these only 17 have hitherto been found in the Norwegian 

 fjords. Indeed the fjord fauna is very distinct from that of the British 

 area, almost as distinct perhaps as the latter is from the Mediterranean 

 fauna. 



The distribution of one of the new species, Cerebratulus longiflssvs r 

 is very peculiar. So far as is known it occurs only in Norway and in 

 the South Atlantic off Marion Island. At present it remains a puzzle. 



In Linens cinereus, it was found that the oesophageal nerves meet 

 below the oesophagus, which is consequently surrounded by a complete 

 nerve ring. This condition has been found by Punnett in other 

 Heteronemerteans, but in none of the more primitive members of the 

 phylum. 



Incertae Sedis. 



Embryonic Fission in the Genus Crisia.$ — Alice Robertson has 

 studied the budding of the embryo in the genus Crisia. In male- 

 colonies of 0. eburnea a few of the primitive germ-cells which are 

 developed earlier than the polypide buds attach themselves to each of 



* Troc. Linn. Soc. N.S.W., xxvii. (1002, published 1003) pp. 497-51 5 (2 pis.). 



t Bergens Museums Aabog, 1908, No. 2, 85 pp. (2 pis.). 



X Univ. of California Publications, Zoology, i. No. 3, pp. 115-56. pis. 12-15. 



