328 SUMMARY OF CURRENT RESEARCHES RELATING TO 



ledge of the process of fertilisation in different genera, in the hope 

 that observers who have the opportunity will endeavour to fill these 

 blanks. The paper contains some useful hints on habitats, &c, of the 

 less well known species, with notes as to localities where observations 

 may be profitably attempted. 



Nematohelniintlies. 



Moulting and Encystation in Nematodes.* — E. Maupas finds in 

 Cephalobus ciliatus, C. concavus, C. truncatus, Bhabditis pellio, B. caus- 

 saneli, Leptodera appendiculata, Angiostoma limacis, and Tylenchus 

 devastalrix, that the life is divided into five stages separated by four 

 moults. The first four stages are larval, the fifth and last belongs to 

 adult life. Each moult is a complete rejection and renewal of the 

 cuticle. During the exuviation the animals are lethargic for periods 

 varying with the rate of development in the species. Thus in Bhabditis, 

 whose larval life occupies 2-4 days according to the temperature, the 

 quiescent phase does not last for more than two or three hours ; while 

 in Cephalobus ciliatus, which has a larval life of 35-40 days or more, 

 the quiescent stage lasts 2-3 days. The moults correspond to similar 

 stages in development, as shown by the state of the organs generally 

 and of the gonads in particular. Maupas draws an interesting parallel 

 between the moults of Nematodes and those of Arthropods, though he 

 distinguishes the two types of cuticle, and separates moults of metamor- 

 phosis from moults of growth. Encystation may occur between the 

 first and third moult, and replaces the second. It is not a phenomenon 

 sui generis, but should be regarded as an adaptive modification of 

 the moult. The cyst is incontestably the homologue of the second 

 exuvial casting. Of course, the cysts of Trichina, &c, are of a different 

 nature, and should rather be called capsules. 



Only the larvae of the second stage seem to have the power of true 

 encystation, and the chief condition of it is scant nutrition. It is an 

 adaptation to avoid death. Experiments on Bhabditis teres show that 

 the encysted larvas have often a great capacity of resisting desiccation, 

 but sometimes the power is very slight. The power of revivification 

 is a special adaptation to particular conditions of life, and, like all 

 adaptations, it is subject to variation. 



Filaria of Human Eye.j — Dr. F. Supino has investigated the species 

 of Filaria from the human eye which Grassi called F. inermis, and has 

 come to the conclusion that it is identical with F. apapillocephala Cond., 

 F. palpebralis Pace, F. •peritonei hominis Bab., F. conjunctivae Add., 

 F. dubini Cond., F. oculi asini Cond., and F. lentis Dies. 



Filaria loa.J — Prof. E. Blanchard gives a detailed account of this 

 parasite, which occurs beneath the conjunctiva in negroes from the 

 West Coast of Africa. The author studied a mature male and an imma- 

 ture female. 



* Arch. Zool. Expe'r., vii. (1899) pp.*563-628 (3 pis.), 

 t Atti. E. Accad. Lincei (Rend.), ix. (1900) pp. 85-91 (3 figs.). 

 \ Arch. Parasitol., ii. (1S99) pp. £01-34 (2 tigs.). See Zool. L'entialbl.. vii. (1900) 

 pp. 243-4. 



