SCIENCE-GOSSIP. 



have come from their various tributaries, which 

 stretch all through the north, south and west of 

 Yorkshire, and in the case of the Trent, much of 

 the material is brought from the Midlands, and 

 even from the far side of the Pennine Chain. 



The rocks found in the boulder clays, though of 

 course only a small proportion of the bulk of the 

 cliffs of Holderness, are precisely similar to those 

 which the rivers at their sources pass through, 

 and the problem is all the more complicated by 



the fact that the rivers traverse boulder clay areas. 

 A priori, therefore, it would seem useless micro- 

 scopically examining the particles in the Humber 

 in order to ascertain their origin. The subject can 

 only be viewed from a common-sense point of view, 

 in which case it must be admitted that although a 

 fair amount of sediment may be carried into the 

 estuary by means of the rivers, the bulk of it is 

 derived from the Holderness coast. 

 76, Sherbiirn Street, Hull. 



BRITISH INFUSORIA, 



By E. H. J. Schuster, F.Z.S. 



Part I. — Flagellata Eustomata. 



(Continued from Vol. iv. page 347.) 



A LL the species hitherto described in this 

 article have belonged to the family Eug- 

 lenidae. We will now pass on to descriptions of 

 commonly occurring representatives of some of the 

 other families, viz., Astasiadae, Chrysomonadidae 

 and Anisonemidae. 



The Astasiadae are thus characterized by Saville 

 Kent : " Animalcules mostly free swimming, ex- 

 ceedingly plastic and variable in form, bearing a 

 single terminal flagellum, oral aperture distinct, 

 endoplasm colourless." 



Astasia, trichophora Ehr. — The body of this 

 animal is highly metabolic and changeable in 

 shape. When fully extended, it is pear-shaped, 

 or almost triangular, and 40 to 60 microns in 

 length ; the posterior portion is broad and the 

 anterior tapers off to a point. The oral aperture is 

 near the anterior extremity, and leads into a 

 straight, tubular and conspicuous pharyngeal tract. 

 Near the middle of this the contractile vacuole is 

 situated. This organ, according to Biitschli, is not 

 simple and spherical, but possesses lateral branches, 

 into which the water is partially driven on con- 

 traction or systole. The endoplasm is colourless, 

 and contains a large central spherical nucleus. 

 The flagellum is thick and conspicuous, and about 

 one and a-half times as long as the body ; it is 

 borne at the anterior end. The motions of the 

 animal are of two kinds, swimming and body 

 movements. The former is slow and steady and is 

 brought about by wave-like vibrations of the 

 anterior half of the flagellum, the posterior or 

 basal half being kept almost steady and pointed in 

 the direction in which the animal is moving. The 

 other movement is effected by variable puckering 

 of the cuticular surface and a more or less longitu- 

 dinal contraction of the body : it is almost 

 painful to see, resembling the writhing s of an 

 animal in sore distress. 



The species was described by Ehrenberg, who 

 mistook the basal half of the flagellum for an 

 anterior neck-like prolongation of the body, as in 

 Trachelitis trichophora ; but as subsequent investi- 

 gators found out his mistake, this euphonious 

 designation, so unlike the usual jaw-dislocating 



Fig. 8. — Astasia trichophora. 



a, Expanded condition as when swimming (x 500). 

 b, c, Position when writhing ( x 500). 



combinations of sounds with which science has 

 made us familiar, had to be with sorrow abandoned. 



This animal is to be found usually in ponds and 

 stagnant water, but owing to the numerous 

 different shapes assumed by the body it might 

 easily escape recognition. De Fromentel, in his 

 "Etudes sur les Microzoaires " (Paris, 1876), gives 

 a long list of various species of Astasia : A . atriculns, 

 A. de/ormis, A. turbo, A. ftisiformis, A. crassa and A. 

 regularis ; which, from his descriptions and figures, 

 might easily be some of the various protean phases 

 of A. trichophora. 



A stasia flavicans Ehr. — This species is subfusiform 

 in shape, the posterior extremity is produced into 

 a blunt tail-like process, and the anterior extremity 

 is somewhat rounded. The greatest diameter is 

 behind the centre. The protoplasm contains 

 numerous granules of a dull yellowish colour. 

 The length of the body is about 50 microns, and 

 the flagellum is twice this proportion. The 



B 3 



