ZOOLOQY AND BOTANY, MICROSCOPY, ETC. 639 



each with a central corpuscle, or in that of Acineta fcetida, formed of 

 a sarcodic network with irregular meshes. These two arrangements 

 are also found, the former among ciliated Infusoria, Glimacostomum 

 virens and Uroleptus pisds, the latter in another Acinetan, Dendroco- 

 metes paradoxus. 



As to the nucleolus, Stein affirms that no trace of one has ever 

 been found, whilst Koch, Hertwig, and Biitschli do not refer to it. 

 Fraipont alone states that he has found within the nucleus of Opliryo- 

 dendron behjicum, Acineta tuberosa, and A. vorticelloides, one or more 

 much darker corpuscles of nucleolar appearance ; but Koch has studied 

 a species of the first genus and Hertvig A. tuberosa without finding 

 any nucleolus, and the observations of Fraipont are too doubtful to be 

 accepted. The author has, however, examined A. foetida and Podo- 

 phrya limbata, and has always found a nucleolus exterior to the nucleus, 

 and similar in form and size to the nucleolus of the ciliated Infusoria. 

 The animals were killed with a 1 per cent, sjlution of acetic acid or 

 by the vapours of a solution of osmic acid of similar strength, then 

 coloured with carmine, and after being washed, cleared with pure 

 glacial acetic acid, for which was finally substituted glycerine, leaving 

 it to penetrate in proportion as the acid evaporated. 



Our knowledge of the Acinetidse is, in M. Maupas' view, much 

 too incomplete to definitely establish their systematic position in the 

 Protozoa. Too much has been made of some of their resemblances to 

 the Ciliata, whilst the considerable and fundamental differences have 

 been neglected. If the author were asked to what group they have 

 the most affinity, he would reply that they have much affinity with 

 the Heliozoa. There is a great resemblance in the disposition, struc- 

 ture, and the mode of action of the pseudopodia of the latter and the 

 tentacles of the Acinetidse. This resemblance is still more striking 

 when we remember the manner in which Podoplirya Trold, according 

 to Claparede, devours its prey, the suckers enlarging enormously and 

 swallowing their captives, making them penetrate whole into the body, 

 instead of sucking them slowly as in the other Acinetidae. This mode 

 of prehension of the food much resembles that of Actinosphosrium 

 Eiclihorni, and gives us one more link between the two kinds of organs. 

 " Are we then to consider the Acinetans as derived from the Heliozoa ? 

 I think that would be going much too fast. . . . Between these two 

 groups of Protozoa there exist, particularly in the phenomena of 

 reproduction, differences too great for it to be possible to admit a 

 direct filiation. Let us be content for the present with having 

 indicated their points of resemblance wuthout wishing to deduce 

 consequences to which perhaps they do not lead." 



New Type of Porcellanous Foraminifera* — Mr. H. B. Brady 

 describes from the ' Challenger ' expedition a new genus and species 

 (Keramosplicera Murrai/i), which illustrates a very distinct and inde- 

 pendent type of foraminiferal structure not previously described, 

 though closely related to certain well-known porcellanous forms, and 

 presenting a certain analogy to Orbitolites. 



* Ann. and Mag. Nat. Hist., x. (1882) pp. 242-5 (1 pi.). 



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