ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 615 



With the exception of Europe the localities in which fresh-water 

 sponges have been found are few and far between, and no notice has 

 been published of their occurrence in Africa. It may be fairly- 

 inferred that a great many more species will be discovered there as 

 well as elsewhere, and Mr. Carter considers that we are only on the 

 threshold of our knowledge of the extent and varieties of the fresh- 

 water sponges, so vast are the fresh-water areas which have not been 

 explored. 



Sponge Spicules in Chert.* — Professor W. J. SoUas confirms his 

 detection of sponge-spicules in chert from the carboniferous lime- 

 stone (Ireland). In some slides which he examined the chief deter- 

 minable constituents were sponge-spicules, making up the larger part 

 of the chert. 



Protozoa. 



Kent's ' Manual of the Infusoria.' f — Four parts of this work 

 (to be completed in six parts of about 800 pp. and 48 plates in all) 

 have been issued. 



Chapter I. is " Introductory," and contains a chronological sum- 

 mary of the General History of the Infusoria from the time of their 

 discovery by Leeuwenhoek in 1675 to the year 1880. Chapter II. 

 " The Sub-kingdom Protozoa," contains the taxonomical, biological, 

 and structural values and affinities of the various groups of Infusoria, 

 with suggestions for their classification. The Spongida and Myxo- 

 mycetes or Mycetozoa are treated as belonging to the Protozoic system. 

 The Protozoa are divided into four principal sections. (1) The 

 Pantostomata, without any proper oral orifice, food being incepted 

 indifferently throughout the body. These include the Amoebina, 

 Gregarinida, Foraminifera, Eadiolaria, and some of the Flagellata. 

 (2) The DiscosTOMATA, also without distinct oral orifice, the inception 

 of food being limited to a discoidal area occupying the anterior ex- 

 tremity of the body. This division contains the collar-bearing Flagel- 

 lata (Choano-Flagellata of the author) and the Spongida. (3) The 

 EusTOMATA, having a true mouth and containing the majority of those 

 organisms that collectively constitute the class Infusoria, in the more 

 modern use of the term, embracing the Ciliata, the Cilio-Elagellata, 

 and such Flagellata as Euglena and Chilomonas ; and (4) The Poly- 

 STOMATA, with tentacle-like organs radiating from the periphery, each 

 of which serves as a tubular sucking-mouth or for grasping food (and 

 therefore described as " many-mouthed "). Here are placed the 

 Suctorial Animalcules or Tentaculifera of Huxley (Acineta, &c.) 

 Chapter III. is on the " Nature and Organization of the Infusoria," 

 and deals with their morphology, cuticular elements or ectoplasm, 

 internal elements or endoplasm, excreted elements, encystment, loco- 

 motive and prehensile appendages, oral aperture or cytostome, anal 



* Ann. and Mag. Nat. Hist., vii. (1881) pp. 141-3 (2 figs.). 



t Kent, W. S., ' A Manual of the Infusoria, including a description of all 

 known Flagellate, Ciliate, and Tentaculiferous Protozoa, British and Foreign, 

 and an Account of the Organization and Affinities of the Sponges.' (8vo, London, 

 1880-1.) 



