3 o8 



SCIENCE-GOSSIP. 



The body is usually not held in the same straight 

 line as the stalk, but makes an angle with it ; to 

 this fact the specific name is due. The length of 

 the body is from 75 to 90 microns. The stalk is 

 three or four times this length. 



The animal may usually be found in large 

 clusters growing on algae in stagnant water. 



Zootliamnium affine Stein is a colonial form 

 closely allied to Vorticella. It consists of a 

 number of individuals, rarely exceeding four, 



Fig. 37. — A small colony of Zoothamniiun affine. 



Consisting of two individuals. One is shown expanded, the 

 other contracted. 



arranged on a dichotomously branching stalk. 

 The individuals are ovate in shape, about one 

 and a-half to twice as long as broad, resembling 

 structurally a Vorticella with an exceedingly thick 

 peristome. The stalk is highly retractile and has 

 a muscle band running continuously through it. 

 It is very thick and its surface is marked with a 

 number of transverse folds. The length of the 

 body is about 90 microns. The stalk is twice or 

 three times this length. 



Colonies of Zootliamnium often infest the legs of 

 Gammarus pidex. I have found them in this position 

 on specimens of Gammarus taken near Oxford. 



Epistylis anastatica Linnaeus. — The genus Epistylis 

 is also colonial. It differs from Zootliamnium in 



Fig. 38.— Epistylis anastatica. 

 a, a colony. One half of the colony is shown bare of 

 Individuals ; b, individual expanded ; c, contracted individual. 



the nature of the stalk, which is non-retractile 

 in the former and retractile in the latter. The 



colonies of E. anastatica consist, when fairly old, 

 of a large number, usually from one hundred to 

 two hundred, of individuals growing on a dichoto- 

 mously branched stalk ; the primary branches of 

 this are greater in diameter than the secondary 

 branches, and the secondary than the tertiary, and 

 so on. Each individual resembles Vorticella fairly 

 well in general structure. The body is sub-conical 

 when fully expanded, and three or four times as 

 long as broad. It is very retractile, and is drawn 

 back and shut up into a sub-spherical body whose 

 diameter is about one third of the length of the 

 expanded individual. The cuticular surface is 

 marked, particularly distinctly in individuals of 

 young colonies, with transverse striae set closely 

 together. The macronucleus is very long and 

 band-like, stretching almost throughout the whole 

 animal, the micronucleus is small and lies by it. 

 The length of the body when expanded is from 

 80 to about 130 microns. 



I have found this species to occur in great pro- 

 fusion on Cyclops. It can be easily recognised with 

 the naked eye. 



I cannot conclude this series of articles without 

 acknowledging an obligation to Mr. Saville Kent's 

 monumental work " The Manual of the Infusoria." 

 The existence of a treatise so useful to all interested 

 in Protozoa is admirable, and the fact that it is 

 written in English adds to its value among workers 

 speaking that language. 

 Next) College, Oxford. 



Permanent Stain for Starch.— Mr. J. H 

 Schafmer, writing in the " Journal of Applied 

 Microscopy," states that a good and durable stain 

 for starch may be obtained by the use of aniline- 

 safranine and gentian-violet. (1) Aniline-safranine: 

 alcoholic fifty per cent, solution prepared by com- 

 bining equal parts of aniline water and a saturated 

 alcoholic ninety-five per cent, solution of safranine. 

 (2) Gentian-violet : a two per cent, aqueous 

 solution. Stain from two to four hours in the 

 safranine, and from two' to eight minutes in the 

 gentian- violet. The slide should be taken through 

 the alcohols quite rapidly, or too much of the 

 stains will be washed out. Mr. Schaffner has tried 

 this on several kinds of starch, always with good 

 results. Some slides with sections of the corms of 

 Erythronium, which were stained over two years 

 ago, are still of the same colour and intensity as 

 they were the day they were mounted. The stain 

 is a clear purplish red, and makes a good object for 

 demonstration purposes. Paraffin sections of the 

 young corms of Erythronium are especially 

 favourable objects for showing the position of 

 starch in cells, and by using the above method of 

 staining the cells will look perfectly clear filled 

 with the coloured starch grains. 



