ZOOLOGY AND BOTANY, MICROSCOPY, ETC 49 



cells tli.it occur in the endothelium of the vessels. The urns arise both 

 on the inside and on the outside of the tentacular vessels, and there is 

 no real difference between those which remain sedentary and those which 

 become free-swimming. There is no doubt that they arise from the 

 Sipunculid-tissue. They are not parasites. They are not phagocytic, 

 but they help, as Cuenot pointed out, to purify the ccelomic fluid by 

 collecting and agglutinating particles. They are, perhaps, comparable 

 to the ciliated organs connected with the nephridia of Hirudinea, which 

 are also derivatives of peritoneal tissue. 



Reproductive Apparatus of Kynotus.* — L. Cognetti de Martiis 

 describes the gonads and associated structures in this peculiar Madagascar 

 genus of earthworms, and fills up the gaps in the previous descriptions 

 by Rosa, Benham, and Michaelsen. 



Calciferous Glands of Earth worms. t — A. Combault suggests that 

 these glands have some respiratory significance. They may fix the CO., 

 and thus avoid asphyxiation. The concretions may be the result of 

 the fixing of the CO., in the glands. Some specimens of Helodrilus 

 caliginosus sub-sp. trapezoides, were placed in very dilute lime-water ; 

 after 24 hours the glands were loaded with carbonate of lime. Further 

 experiments confirmed this. 



Nematohelminthes. 



Free-living Nematodes. J— J. G. De Man describes 18 species of 

 free Nematodes, all of which (except Eurgstoma terricola sp. n., from 

 the soil) have been collected on the coasts of Zealand. Thirteen are 

 new, e.g., jfflgialoalaimus elegans g. et sp. n., Gobbia trefusiceformis g. et 

 sp. n., Parasabatieria vulgaris g. et sp. n., and Metalinhommus tgpicus 

 g. et sp. n. A useful list is given of all the free marine Nematodes the 

 author has found on the coasts of Zealand. 



Toxic Effect of Sclerostomum equinum.§ — M.Weinberg has ex- 

 perimented with extracts of this parasite, and has obtained rather 

 important results. He finds that these extracts dissolve the red blood- 

 cells of the horse. The toxic substance is secreted especially by the 

 cephalic part of the parasite, and also by the digestive tube ; it is 

 resistent to a temperature of from 115-120° for 15-20 minutes, and is 

 not specific for the horse, since it acts similarly upon the blood-cells of 

 guinea-pig, rabbit, ox, and sheep. Sclerostomes also secrete a substance 

 with the properties of a precipitin with horse and with rabbit serum. 

 Extracts of larvas have a similar but less marked effect. Other hel- 

 minths found in the horse {Oxguris equi, Ascaris megalocephala, Tamia 

 perfoliata, Tcmia plicata) do not secrete a heematoxin ; it is noteworthy 

 that the only parasite capable of doing so is the only one which lives on 

 the blood of the horse. 



* Atti R. Accad. Sci. Torino, xlii. (1907) pp. 1138-50 (1 pi.). 

 t C.R. Soc. Biol. Paris, lxii. (1907) pp. 440-2. 

 % Tijdschr. Nederland. Dierk. Ver., x. (1907) pp. 227-44. 

 § Ann. Inst. Pasteur, xxi. (1907) pp. 798-807. 



Feb. 19th, 1908 e 



