ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 95 



is borne in mind, it is impossible to homologize it with the circlets of 

 worms. In the latter the preoral circlet surrounds the frontal area, and 

 within it the brain arises ; but in the Eotatoria the brain always lies out- 

 side the wheel-organ, which does not inclose the frontal area. 



The lobate structures which are found round the mouth of all rota- 

 torian larvae appear to the author to be remnants of the largely developed 

 lobate appendages of turbellarian larvse. 



Although there are close anatomical resemblances between the excretory 

 organs of worms and Eotifers, they must not be supposed to have arisen in 

 the latter from the former; the point of union between Annelids and 

 Eotifers must be sought for deeper down in the scale of animal organiza- 

 tion — in the Turbellaria. 



The mode of origin of the mesoderm opposes the view that Annelids 

 and Eotatoria are closely allied, for in the latter it arises at the anterior 

 lip of the prostoma, and in all the former at the hinder end of the body ; 

 the mesoderm of Eotatoria can only have been developed from a not yet 

 definitely localized mode of formation of the mesoderm, such as obtains 

 among the Turbellaria. 



With regard to an affinity between the Eotatoria and the Crustacea, the 

 mode of origin of the mesoderm offers some support ; the reduction of the 

 postabdomen is another point of similarity, as is also the dorsal position of 

 the anus. The jointing and forking of the same region recalls the Cope- 

 poda, and seems to be an important characteristic. The absence of a 

 ventral medulla is against crustacean as well as annelidan affinities. ^ 



The author thinks he has justified the removal of the Eotatoria from 

 the " class of worms," and ascribes to them a position intermediate between 

 the lower worms and the lower crustaceans. In the system they must 

 form a special division between Vermes and Crustacea. 



Natural History of Orthonectida.* — M. E. Kohler finds that BTiopa- 

 lura is found rather more abundantly in those Ophiurids which dwell 

 among the tubes of Serpula PMUppii than in those which live quite freely. 

 Parasites are rarely found in specimens that have been in glasses for some 

 days. Both males and females were frequently found in the same Ophiurid, 

 and the males are always more abundant than the females. Contrary to 

 the observations of Julin, the author failed to find that the season had any 

 modifying influence on the proportion of the sexes. 



Two New Species of Balanoglossus.f — Prof. A. P. Marion gives a 

 detailed account of the two new species of Balanoglossus, whose characters 

 were indicated in a note already referred to in this Journal.J Information is 

 now given as to the results of an examination of transverse sections, as to 

 which the author is very detailed, but he abstains from any generalizations. 



Ccelenterata. 



Polypes turned outside in.§ — Herr M. Nussbaum gives an account of 

 experiments on Hydra, in which he tested the often-repeated assertion, 

 based on the authority of Trembley, that in a Hydra turned outside in, 

 ectoderm became endoderm, and endoderm ectoderm, and all was again in 

 statu quo. This is not the case. After a time, according to Nussbaum, 



* Comptes Eendus, ciii. (1886) pp. 608-10. 

 t Arch. Zool. Exper. et Gen., iv. (1886) pp. 305-26 (2 pis.). 

 X See this Journal, 1886, p 252, 



§ Biol. Oentralbl., vi. (1886) pp. 570-2. (Ber. 59 Versamml. Deutsch. Naturf. 

 u. Aertze, Berlin, 1886). 



