192 SUMMARY OF CURRENT RESEARCHES RELATING TO 



neither collect in carbonic or other acids, and were not observed to 

 form spontaneous gatherings. 



Comparative Morphology of Hypotrichosis Infusoria. * — Hans 

 Wallengren points out that, although it is well known that the cirri in 

 the Hypotricha are very different in the newly formed daughter-cells 

 and in the adult, and undergo a series of changes after the division, yet 

 these changes have not as yet been worked out in detail. There can be 

 no doubt that the Hypotricha which are most richly ciliated are more 

 primitive than those in which the cilia are reduced in number, and on 

 the basis of this assumption the author has worked out the changes 

 undergone during and after division by a series of forms, choosing both 

 primitive and differentiated types. The object of the investigation was 

 to determine whether or not homologies exist between the cirri of the 

 different forms. Prior to division the old cirri are absorbed, and six 

 rows of cilia appear, whose members undergo changes of position, and 

 become ultimately transformed into the adult cirri. In the five species 

 •studied these six rows are all homologous, and it is possible to derive 

 the adult condition in each case from a type by varying degrees of re- 

 duction, the reduction always taking place after a precisely similar 

 fashion. 



New Ciliata. j — Max Voigt describes, from the lakes of Plon, 

 Didinium cinctum sp. n., a brown, free-swimming Protozoon with a ring 

 of cilia round the anterior distended part of the body and six longi- 

 tudinal rows passing backwards from this. The mouth is at the anterior 

 end, and the contractile vacuole close to the posterior end near the anus. 

 On Canthocamptus staphylinm the author also took a new stalked Proto- 

 zoon with a test which he places in the genus Cothurniopsis as C. longipes 

 sp. n. The stalk is very long, and each test contains two individuals. 



New Species of Peridinium.J — Dr. A. Garbini describes Peridinium 

 alatum sp. n., a new member of the plankton of the Lake of Monate. 

 It closely resembles P. tabulatum in general appearance, but differs in 

 the presence of three rigid, membranous wing-like structures. Of these, 

 two are anterior and ear-like, the third posterior, and resembling a caudal 

 tfin. All are transparent and delicately undulated. In the same paper 

 the author gives a list of the commoner members of the plankton of the 

 lake. 



Adaptability of Infusoria to Concentrated Solutions.§ — Eomuald 

 Minkiewicz states that Atsuschi Yasuda,|| in his paper bearing the above 

 title, has greatly minimised the value of his observations by a want of 

 ■care in the identification of the species employed in the experiments. 

 He maintains especially that the form described by Yasuda as Mallo- 

 monas plosslii is not a species of Mallomonas at all, but is a species of 

 Cyclidium, and is shown by the author's own figure to be totally devoid 

 of the brown chromatophore characteristic of Mallomonas as of other 

 Chrysomonadina. 



* Handl. K. Svensk. Vet.-Akad., xxvi. (1901) pp. 1-31 (18 figs.). 

 + Zool. Anzcig., xxv. (1901) p. 36. 



\ Tom. cit.. pp. 123-4 (2 figs.). § Tom. cit., pp. 124-5. 



|| Journ. Coll. Sci. Imp. Tokyo, xiii. (1900) pp. 101-40 (3 pis.). 



