7"-> 



ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 17 



Incertee Sedis. 



Regeneration in Enteropneusts.* — 0. Dawydoff has studied this in 

 Ptychodera minuta and in a Xew Guinea species. It appears that the 

 regenerative processes pursue a somewhat palingenetic poth. In some 

 cases the regeneration is atavistic. But there is no fundamental differ- 

 ence between the ordinary ontogeny and the regenerative development. 

 Dawydoff uses his results to throw light upon some morphological ques- 

 tions, e.g. the significance of the proboscis-ccelom and its relations to the 

 pericardium. In regard to the so-called " notochord," he is of opinion 

 that it corresponds to a pre-oral region of the gut, which previously 

 functioned as a gullet. The proboscis pores of Enteropneusts represent 

 an organ which has changed its function, and is homologous with the 

 metanephridia of Annelids. 



Studies in Tardigrada.f — Ferd. Richters describes several fresh-water 

 species of Makrobiotus ; a marine form, Tetrakentron synaptse Cuenot, 

 parasitic on Synapta ; Batillipes minis g. et sp. n., another marine type. 

 Sis marine genera are now known— Lydella, Echiniscbides, Tetrakentron, 

 Makrobiotus, Halechiniscus, and Batillipes. Richters maintains that the 

 Tardigrada are related rather to the Annelids than to the Arthropods, 

 finding arguments in a seta-like nature of the " claws " in many types 

 and in the cirri in others. 



Rotifera. 



Distribution of Rotifera.! — C. F. Rousselet discusses the results of 

 recent investigations with regard to the geographical distribution of 

 Rotifera, and arrives at the conclusion that most of these creatures 

 enjoy an almost cosmopolitan range all over the world, and that it is not 

 possible to speak of any typical or peculiar Rotatorian fauna for any 

 continent, zone, or region. Numerous examples are given of rare species 

 appearing in widely separated localities, indicating that distance is no 

 obstacle to their distribution, provided only that suitable conditions are 

 encountered. The fact that some few Bdelloid Rotifers can come to 

 life again after a prolonged desiccation does not sufficiently account for 

 this wide range. The author considered that it is their resting eggs, 

 which are able to resist both desiccation and low temperatures, and can 

 moreover readily be transported by the wind to any distance, which are 

 the main cause of this cosmopolitan distribution of the Rotifera from 

 the equator to the polar regions. 



Rotifera of Turkestan. § — E. von Daday has examined some Plankton 

 material collected by D. D. Pedaschenko in two inland seas in Turkestan, 

 and found therein amongst other creatures eleven species of Rotifera, 

 one of which the author describes as new under the name of Pedalion 

 mucronatum. This same species has, however, previously been found 

 in the Aral Sea and described by Gernow in 1903 as P. oxyure, which 

 name therefore has priority. It resembles most nearly P. fennicum 

 Levander, but differs from it in the possession of a pointed posterior 

 prolongation of the body. 



* Zeitschr. wiss Zool., xciii. (1909) pp. 237-305 (4 pis. and 23 figs.), 



t Ber. Senck. Nat. Ges., xl. (1909) pp. 28-48 (2 pis.). 



\ Journ. Quekett Micr. Club, x. (1909) pp. 465-70. 



§ Trav. Soc. Imp. Nat. St. P6tersbourg, xxxix. (1909). 



