574 ABSTRACTS OF MEMOIRS. 



set free on the disintegration of the corpuscles, and that their action 

 on the protoplasm of the corpuscles is merely catalytic. This sub- 

 stance, produced from the blood corpuscles, is probably a fluid, and 

 would be slowly and continuously formed as long as blood corpuscles 

 could pass through the walls of the cyst. The action of this substance 

 on the fibroblasts forming the walls of the cyst is to delay their return 

 to the spindle shape typical of the resting condition, and eventually to 

 set up those changes in the inner layer of fibroblasts resulting in their 

 conversion into ciliated epithelium. 



G. H. D. 



A Review of the British Marine Cercariae. By Marie V. Lebour, 

 M.Sc. {Parasitology/, Vol. IV, No. iv, January, 1912.) 



The work in this paper on Spdotrema exccllens Nicoll was partly 

 carried out at Plymouth in April, 1911. The first host of this worm 

 seems most commonly to be Littorina oUusata ; L. rudis and Paludes- 

 trina staffnalis are also first hosts for it. The tailed cercaria occurs in 

 sporocysts in the digestive gland of these molluscs, and possesses a 

 stylet in its head by w^hich presumably it bores its way into its second 

 host, the green crab, Carcinics macnas. Here it encysts and gradually 

 enlarges, loses its stylet, and assumes the Spelotrema form, the walls 

 of the cyst thickening until a certain size is reached, when the cercaria 

 rests. The full-grown cysts are found all the year round, but no 

 young stages in the winter. All the Plymouth crabs seem to be 

 infected and in almost every organ, the digestive gland and muscles 

 being the favourite parts. The final host of the worm is probably the 

 herring gull, Lams argcntatus. 



M. V. L. 



Contributions to the Knowledge of the Laminarias. {Beitrage zur 

 Kenntnis der Laminarien.) By C. Killian. {Zeitschrift fur 

 Botanik, 1911, Heft 7.) 



Notwithstanding the large number of papers on Laminaria, its 

 development was until recently but little understood, for it was only 

 in 1910 that Drew published an account of the first successful cul- 

 tures. Thanks to the previous work of that author, the writer 



