ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 75 



ment and its appendages are described ; though the author was able 

 to examine the genital organs, he was not successful in finding fer- 

 tilized ova. Of the Alciopida3 five species are enumerated, four of 

 which — Vanadis melanophthalmus, V. setosa, JRhynchonerella fnhjens, 

 and Alciopa longirlujnclia — are new. The male of B,. fulgens is re- 

 markable for the arrangement of its generative organs ; from the tenth 

 to the thirteenth segments there are a pair of coiled tubes filled with 

 spermatozoa; the orifices at either end are very fine ; the tubes com- 

 municate with very peculiar conical organs lying under the j)arapodia 

 of their proper segment, at the end of which they open to the exterior. 

 Uufortunatsly with the Alciopidte also Dr. Greef was unable to make 

 any observations on development or on the larvae. 



Development of Nematoids.* — M. P. Hallez has made some 

 further! observations on the development of round worms, which 

 justify him in doubting the correctness of two of the conclusions 

 reached by Davaine. That author stated (1) that the embryo only 

 escaped from the egg after it had been brought into the intestine with 

 food or drink, and (2) that the softening of the egg-shell by the in- 

 testinal juices and a temperature of about 40"^ C. were necessary for 

 the escape of the eggs ; but Hallez found that, having placed on the 

 18th of June a number of eggs of Ascaris megalocepJiala on the surface 

 of the earth of flower-pots, a number of embryos escaped on the 

 succeeding 17th and 18th of August. This and other experiments 

 appear to be conclusive as against the accuracy of Davaine's laws. 

 The young never escape if the eggs are put into water, or are allowed 

 to dry; the young, both before and after their escape, require a 

 supply of oxygen, and this may be the reason why they do not 

 develope under water. 



Nervous System of Taeniadse.l— The nervous system of Cestodes, 

 first recognized about fifty years ago, but till within the last decen- 

 nium generally ignored or denied, has recently been the subject of 

 frequent research. The current description, according to which the 

 nervous system consists of spongy lateral cords, has been proved 

 inadequate, but the observations have been hitherto too conflicting 

 and fragmentary to admit of any definite conception of the real state 

 of the case. Through the work of Dr. J. Niemiec, however, the pre- 

 ceding researches have been corrected, completed, and unified, and 

 the Tseniadse have been shown to possess a nervous system of great 

 complexity. 



The research is based on sections of the scolices of T. coenurus, 

 T. elliptica, T. serrata, and T. mediocanellata. After giving an account 

 of the arrangement and histology of the musculature, he unravels the 

 intricate maze of cords and commissures in the four above-named 

 species. Only a brief account of his summarized results can be given. 



(a) The nerve-ring. — A nerve-ring situated under the hooks, pre- 

 viously observed by Moniez in one species, has been demonstrated in 



* Comptes Rendus, ci. (1S85) pp. 831-4. 



t Sec this Journal, v. (1885) p. 809. 



I Kecueil Zool. Suisse, ii. (188.5) pp. 589-648. Sec this Juuiual, v. (1885) p. 244. 



