ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 397 



List of Mr. Carter's Genera and Species of Sponges.* — Mr. A. 



Dendy has prepared an alphabetical list of the genera and species of 

 sponges described by Mr. H. J. Carter, together with a number of his 

 more important references to those of other authors, which will doubtless 

 prove a useful guide to students of this group. 



Protozoa. 



Biitschli's Protozoa.j — Prof. O. Biitschli completes his account of 

 the morphology of the Ciliata, and commences the systematic descrip- 

 tions. In the former, division, formation of colonies, conjugation and 

 copulation, and encystation are discussed. The systematic part begins 

 with an historical introduction in which the chief earlier classifications 

 are tabulated ; of the origin of the group we know but little, and we can 

 almost certainly state that no other group of animals is derived from 

 them. There are from 450 to 500 more or less well known species ; 

 twenty-seven genera are exclusively marine, and there are from 170 to 

 200 marine species ; twenty-four genera are exclusively parasitic. It 

 cannot be certainly said that Multicilia or Grassia are true Ciliates. 

 The first order of true Ciliata are the Gymnostomata of Biitschli, which 

 represent part of Stein's Holotricha ; the families of this order are 

 Euchelina, Trachelina, Chlamydodonta. The second order is that of 

 the Trichostomata, which is equal to part of the Holotricha plus the 

 Spirotricha ; its first suborder is that of the Aspicotricha, which is 

 equivalent to the old family Paramsecina. 



Merotomy of Ciliated Infusoria.^ — M. E. G. Balbiani has a contri- 

 bution to the study of the physiological role of the nucleus of the cell. 

 By the term merotomy he means the operation which consists in cutting 

 oil' from a living organism a more or less considerable portion, with the 

 object of studying the anatomical or physiological modifications of the 

 separated part. The account of the experiments commences with a 

 detailed notice of the structure of Cyrtostomum leucas ; the study of the 

 effects of merotomy showed that a fragment of an individual, or mero- 

 zoite, which contains the nucleus is alone capable of regeneration, that 

 is to say, of reconstituting a complete individual which presents all the 

 characters of Cyrtostomum. This regeneration is completed in twenty- 

 four or forty-eight hours, at the latest ; the regenerated individual only 

 differs from an ordinary one in its smaller size, and this is correlated with 

 the size of the fragment from which it took its origin. The regenera- 

 tion of the specific form and of the organs is effected under the influence 

 of the nucleus, for such regeneration is never observed in fragments 

 which have no nucleus. This nucleus has even the secretion of the 

 cuticle under its influence ; the cicatrization of the parts is effected by 

 the secretion of a new cuticle at the point of denudation. The nucleus 

 also appears to play a part in the trophic phenomena of the protoplasm, 

 for this becomes gradually disorganized and finally dies, when deprived 

 of a nucleus. The disorganization of the protoplasm is manifested by 

 the taking-in of water, formation of vacuoles, disappearance of the 

 stratified structure, absorption of the trichocysts and vibratile cilia, the 



* Published by Roy. Soc. Victoria, 8vo, 1888, 26 pp. 



t Bronn's Klassen u. Ordaungen, i., Protozoa (1889) pp. 1585-1712 



X Eec. Zool. Suiifse, x. (18::j8) pp. 1-72 (2 pis.). 



