ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 53 



d. unisetiger sp. n. He likewise describes au abnormality in tbe furca 

 of females of Cyclops ajfinis Sars. 



Hemioniscus Balani.* — M. Caullery and F. IVIesnil have studied 

 this peculiar Cryptoniscid previously described by Bucbholz and by 

 Kossmann. It is a parasite of Balanus balanoides. The male retains 

 many of the characters of a free Isopod. The female arises from a 

 similar larva; in its head and the first four thoracic s-egments it ex- 

 hibits no peculiar feature, but the rest of the body loses its appendages, 

 and becomes a huge sac resulting especially from the hypertrophy of 

 the three last thoracic somites, and prolonged in seven lobes (six lateral 

 thoracic lobes and the posterior abdomen) ; in the adult this sac is full 

 of developing embryos. Kossmann concluded that the female forms 

 arise from the transformation of the male forms, or, in other words, that 

 the animals are protandrous hermaphrodites. 



The authors point out that what Bucbholz called cement-glands and 

 Kossmann regarded as testicular, are glandular organs probably diges- 

 tive. None the less is it true that the male forms show degeneration of 

 the testes ; that these organs are replaced by the ovaries ; that oviducts 

 appear as ectodermic invaginations on forms still recognisably male ; 

 and that the female features are gradually assumed. 



In Hemioniscus the incubatory chamber arises as a solid ectodermic 

 plastron which embraces the oviductal apertures, and is hollowed out by 

 delamination. The ova are fertilised within the oviducts where sper- 

 matozoa have been accumulated, and they pass into the closed incuba- 

 tory chambers without any contact with the outer world. As the 

 embryos grow, the chamber enlarges and encroaches more and more on 

 tbe cavity of the body. The eggs are peculiar in being very slightly 

 pigmented and almost quite alecithal. The blastula is followed by a 

 hollow spherical embryo, bearing the same relation to that of other 

 Epicarids as the mammalian to the Sauropsidan. It is an adaptation to 

 viviparity. 



Is there a Cavernicolous Species of Asellus ? f — Herr C. Miethe 

 gives a detailed description of Asellus cavaticus Schiodte, and comes 

 emphatically to the conclusion that it is a distinct species, and not, as 

 some have supposed, a variety of A. aquaticus. The two species have 

 diverged in different directions from a common ancestral stock. 



Annulata. 



Phagocytosis and Excretion in Annelida.^ — Herr Guido Schneider 

 has made an extended series of observations on this subject by means of 

 physiological injections of coloured fluids, salts of various metals, and 

 particles in suspension. He finds that frequently, though not invariably, 

 the nephridial cells in Annelids are phagocytic. Of the nephridial cells, 

 those which take the most active part in phagocytosis are those which 

 are most actively excretory, that is, are those of the inner loop of the 

 nephridium in Polychsetes, and those of the analogous structure in 

 Oligochjetes. Further, the cells which act as phagocytes in taking up 



* Comptes Eendus, exxix. (1890) pp. 770-3. 



t Rev. Suisse Zool., vii. (1899) pp. 273-319 (3 pis.). 



X Zeitschr. f. wiss. Zool., lxvi. (1899) pp. 497-520 (1 pi.). 



