HARD WICKE'S SCIENCE-GOSSIP. 



in the British Museum, second edition, part i., 

 Andrenidfe and Apidce (London : printed by order 

 of the trustees). We are proud of these two volumes. 

 The trustees of the British Museum are the only 

 authorities who recognise what the Americans have 

 long found out, that science is democratic and not 

 oligarchic. They distribute their valuable volumes 

 with a free hand to every free library and scientific 

 journal. Mr. Bullen's volume will be found of 

 especial value to geologists. It deals practically with 

 the late Mr. Edwards' collection of mollusca. Mr. 

 Edwards was one of the members of the "London 

 Clay Club," founded in 1S3S for the purpose of 

 collecting and describing and illustrating the eocene 

 mollusca. His collection is now in the British 

 Museum, and Mr. Bullen's work is an account of it. 

 The volume on British Hymenoptera is accompanied 

 by a " Catalogue of the British Bees in the British 

 Museum," by Frederick Smith, a new issue. Very 

 few people are aware that the total number of species 

 of British bees known at present is 211. It is 

 hardly necessary to say that Mr. Smith's catalogue 

 is accurately and well done. 



The Medical Annual and Practitioner 's Index, 1 892 

 (Bristol: John Wright & Co.). This volume has 

 gained immensely both in bulk and value since its 

 first appearance ten years ago. It now runs to 

 close upon 700 pages, is abundantly illustrated both 

 by woodcuts and coloured plates, and is contributed 

 to by most of the chief medical writers of the day. 

 Dr. Buffer's paper on "Recent Advances in Bac- 

 teriology " will be read by many other than medical 

 men. We have looked in vain in it for a paper on 

 the "Natural History of Influenza." The volume 

 contains a list of the principal medical books of last 

 year. 



NOTES ON THE INFUSORIA. 



By Bernard Thomas. 



II. — Flagellate Infusoria. 



THE Infusoria proper consists of a single group 

 of unicellular animals. The Diatoms, Desmids, 

 Rotifers and others, either plant-forms or multicellular 

 animals, have been rejected by the zoologist, and 

 referred to their respective classes in the animal or 

 vegetable kingdoms. 



Unicellularity is the leading character of the 

 Protozoa, and while the Arnceba represents the lowest 

 class, the Infusoria is the highest class of that sub- 

 kingdom. The latter are therefore described as a 

 class of the Protozoa furnished either with one or two 

 long motile filaments (flagella), with several delicate 

 vibratile filaments (cilia), or with non-vibralile fila- 

 ments furnished with suckers (tentacles). 



The following is adopted as a good working 

 classification : — 



(1.) Flagellata.* 



(2.) Cilio-flagellata. 



(3.) Ciliata. 



(4.) Suctoria (Acinetoe). 

 (1.) The Flagellata have one or two long delicate 

 filaments called flagella; when two exist, they usually 

 arise from the same, end, and the region from which 

 these organs spring is usually called the oral or 

 anterior end. There is often no mouth, but only 

 an oral region, usually placed near the base of the 

 flagellum, at which the food is introduced. Very 

 generally there is a nucleus, a contractile space, and 

 sometimes a little red pigment body (the so-called 

 eye-spot or red ocellus). 



We may roughly divide the Flagellata into two 

 groups ; firstly, the free-swimming isolated forms, 

 and secondly, those that live in colonies. 



1. Astasia limpida (Fig. 43). The length of the 

 species is given in the " Micrographic Dictionary " 

 as the five-hundred-and-fiftieth of an inch. While 

 swimming, fully extended, it glides along with its 

 long flagellum stretched out in front of it, and this 

 organ may be seen to move about as it swims. It 

 may now be described roughly as shaped like a pear, 

 of which the flagellum forms a somewhat long stalk. 

 The anterior or oral region, from which the fligellum 



Fig. 43 — Astasia limpida. A, extended, showing flagellum (t), 

 vacuole (v), and eye-spot (r o); b, contracted. 



springs in a slight notch, is pointed, the posterior 

 part blunt. The protoplasm in the former region is 

 clear and contains a vacuole, while the remaining 

 substance is granular, sometimes with large well- 

 defined particles crowded close together. In some 

 specimens there is a little reddish body at the 

 posterior end, similar to the eye-spot found in certain 

 of the Alg;e. The flagellum is very long, and seems 

 to be used as a tactile organ, feeling everything that 

 comes in its way. 



From the observations of Butschli t it appears that 



* Clapaiede and Lachmann. 



f "Carpenter on the Microscope," p. 506. 



