ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 291 



to a somewhat fortuitous combination of specific characters such as 

 might arise by occasional hybridization. It has not, however, been 

 experimentally produced. 



Nematohelrainthes. 



Nematodes of Earthworm.* — Gilbert E. Johnson finds that the 

 active larval Nematodes in the nephridia of Lumhricus terrestris and the 

 encysted larvj\3 in the ccelom belong to the same species of Rhahditis, 

 which may be called Rhahditis pellio Biitschli, non Schneider. " The 

 Nematodes removed from the freshly killed earthworm and reared in 

 cultures, or obtained from the dead worm decaying under natural 

 conditions, develop into males and females. Subsequent generations, 

 however, bred under cultural conditions, consist in almost all cases of 

 females only. Examination of these cultures, consisting of females 

 only, reveals the fact that they are in reahty hermaphrodite. Repro- 

 duction is frequently — perhaps always — hermaphroditic. But cases occur 

 in which it appears to be bisexual — that is to say, both hermaphrodites 

 and true females may exist side by side in the same species, as in 

 Rhabdltis marionis Maupas. Xo " partial hermaphrodites " have been 

 found, nor have any cases of *' re-fertilization" been observed. The 

 numerical ratio of males to females is extraordinarily variable, and no 

 iTile governing the fluctuation has yet been found." 



Intestinal Cells of Ascaris megalocephala.f — ^E. Faure-Fremiet 

 finds that the cells lining the intestine contain fats and carbohydrates, 

 such as are also found in the fluid of the cavity of the body. Some 

 oxyhaemoglobin, along with vegetable debris, may be found in the 

 lumen of the gut, the oxyha^moglobin l)eing probably derived from the 

 blood of the horse. Haemoglobin and oxyhaemoglobin may be detected 

 in the perivisceral fluid, having doubtless passed through the intestinal 

 epithelium. In part, however, the haemoglobin is destroyed by the cells 

 of this epithelium, and probably gives origin to the brownish yellow 

 grains seen in the cells. 



Plastosomes of Ascaris megalocephala.J — B. Romeis finds that 

 the plastosomes of the fertilized ovum, partly paternal and partly 

 maternal in origin, show persistence in development. They multiply 

 and share actively in vital processes. They must ba considered in 

 connexion with inheritance. They multiply by dividing off a corpuscle, 

 but differently in different kinds of cells. 



Minute Structure of Oviduct of Ascaris.§ — 0. Zacharias has 

 demonstrated the presence of two nerve-plexuses in the oviduct of 

 Ascaris me</alocephala— one, the plexus subcuticularis, situated close 

 beneath the tunica propria, and the other, the plexus submuscularis, of 

 a more complicated nature, situated on the flat bands of circular 

 musculature. The relations between the second jdIcxus and the muscu- 

 lature recall those on the sub-umbrellar surface of a jellyfish. 



* Quart. Journ. Micr. Sci., Iviii. (1913) pp. 605-52 (1 pi. and 2 figs.). 



t C.E. Soc. Biol. Paris, Ixxiv. (1913) pp. 567-9. 



: Arch. Mikr. Anat., Ixxx. 1 (1913) pp. 129-72 (2 pis. and 2 figs.). 



§ Anat. Anzeig., sliii. (1913) pp. 193-211 (1 pi. and 2 figs.). 



