674 SUMMARY OF CURRENT RESEARCHES RELATING TO 



from the blood. These amcebocytes have pronounced phagocytic pro- 

 perties. At times they increase in size, their substance becomes more 

 liquid, and they surround themselves with a membrane ; tbey may also 

 take up coloured granules. Such modified cells place themselves on the 

 ventral surface of the dorsal vessel and constitute the heart-body ; in 

 structure they closely resemble the chloragogenous cells. They may 

 quit the dorsal vessel and pass into the body-cavity. Without being 

 able to clearly define the relation between phagocytosis, the meta- 

 morphosis of the amcebocytes, and their passage into the body-cavity, 

 the author is yet of opinion that the entire process is excretory in nature. 

 The amcebocytes of the blood multiply by amitotic division, and also 

 originate from a collection of cells along the ventral line of the intestinal 

 sinus. The ccelomic lymphocytes multiply also by direct division, and 

 probably arise from cellular masses on the dissepiments of the Lumbri- 

 culidae. They take part in excretion by taking up the chloragogen, and 

 also substances excreted by the intestinal epithelium. The chloragogen 

 arises probably both from the protoplasm of the chloragogenous cells, and 

 from the cells of the intestinal epithelium, and is an excretory product. 



Variation in Earthworm.* — Mr. Eaymond Pearl describes a re- 

 markable variation of the genital organs in Lumbricus agricola Hoffm. 

 In addition to the two pairs of testes normal for the species, there is a 

 supernumerary pair in somite 12, the lateral seminal vesicles are shifted 

 backwards at the left side, and at that side there is a supernumerary 

 seminal receptacle and a large unpaired supernumerary seminal funnel . 

 There is a supernumerary pair of ovaries, and the left oviduct is dis- 

 placed so as to lie below the supernumerary ovary of that side. It 

 would appear that this displacement is associated with the existence of 

 the extra seminal funnel at that side. The chief interest of the variation 

 the author regards as the evidence it affords of correlation in develop- 

 ment of the different parts of the reproductive system. 



North American Species of Glossiphonia. f — Mr. W. E. Castle 

 describes six species of these Ehynchobdellids, often known by the 

 name Clepsine. There are two distinct groups, the first including 

 G. stagnalis, G. elongata sp. n., G. fusca sp. n. ; the second including 

 G. parasitica and G. elegans, with the closely related European species 

 G. complanata and G. concolor. G. heteroclita occupies a somewhat iso- 

 lated position intermediate between the two groups. 



Nematohelminthes. 



Life-cycle of Filaria bancrofti.} — Dr. T. L. Bancroft has studied 

 the metamorphosis of the young form of Filaria bancwfti Cobb ( = F. 

 sanguinis hominis Lewis, F. nocturna Manson) in the body of Culex 

 ciliaris L., the introduced "house mosquito" of Australia. By feeding 

 the mosquitos on banana he kept infected forms alive for weeks, indeed 

 for a couple of months. Thus mosquitos do not seem to be seriously 

 injured by the filarise. When the young filariae are artificially liberated 

 from the thorax of the mosquito into water, they die in three or four 



* Anat. Anzeig., xviii. (1900) pp. 123-7 (1 fig.). 



t Bull. Mus. Harvard, xxxvi. (1900) pp. 17-64 (8 pis.). 



t Journ. and ±*roc. Ruy. Soc. N.S. Wales, xxxiii. (1900) pp. 4.8-G2 (8 figs.). 



