IO 



SCIENCE-GOSSIP. 



nucleus and contractile vacuole are as in A . 

 trichophora. 



The species may be found inhabiting ditch-water. 



Astasia longifilis Perty. — The body is more per- 

 sistent in form than in the other species. It is 

 subconical in shape and 25 microns in length ; the 

 anterior half is marked by a longitudinal furrow 

 or salcus. The protoplasm encloses some granules 

 of a pale green colour ; the flagellum is at least 

 three times the length of the body. 



This species was taken from a pond on Putney 

 Heath under half an inch of ice. 



There is only one other genus of the family 

 Astasiadae, namely, Colpodella, which was estab- 

 lished by Cienkowski. It differs from Astasia in 

 possessing a suctorial oral aperture, but no pharynx. 

 The following is the one species which he described : 



Coipodella pvgnax Cienkowski. — This animalcule 

 is minute in size and predatory in habits ; it might 

 easily be mistaken for Monas or Paramonas. 



The next family, the Chrysomonadidae, contains 

 a large number of genera and species. I am 

 afraid that it is but poorly represented here. The 

 following are its characteristics as given by Saville 

 Kent. " Animalcules bi-flagellate, rarely mono- 

 flagellate, social or solitary, free swimming or 

 adherent, naked loricate, or immersed within a 

 common mucilaginous matrix or zoocytium ; 

 endoplasm always containing two occasionally 

 green but more usually olive-brown or yellow 

 differentiated pigment bands, one or more supple- 

 mentary eye-like pigment spots usually present." 

 These bands of yellow or green pigment are of 

 firmer consistence than the rest of the protoplasm, 

 and appear to resemble the diatomin or colouring 

 matter of the diatoms. 



Chrysomonas flavicans Ehr. — This species is plastic 

 and changeable in form, the normal shape being 



Fig. 9. — Chrysomonas flavicans (x 500). 



more or less elongate and sub-cylindrical, three or 

 four times as long as broad ; flagellum is single, 

 scarcely equalling the body in length. The endo- 

 plasm encloses two lateral pigment bands, which 

 are lightish green in colour, and do not extend 

 to the posterior margin. The contractile vacuole 

 is large and spheroidal, and situated anteriorly. 

 The nucleus is small and subcentral. The oral 

 aperture is present, but not very much in evidence. 

 The flagellum is single and produced from the 

 centre of the anterior border. The size is from 

 14 to 42 microns. 



The animal lives in ponds and ditch water. 



Cryptomonas erosa, Ehr.' — This is free swimming 

 and solitary ; that is to say, its individuals do 



not grow together in united colonies. Its shape 

 is ovate and compressed, about twice as long as 

 broad, and recurved slightly towards the ventral 

 side. It is rounded posteriorly, and anteriorly 

 bears a prominent lip-like process, from the base 

 of which the two flagella spring. These organs 

 are approximately equal in length. Close to their 

 base is a well-marked oral aperture leading into a 



Fig. 10. — Cryptomonas erosa ( x 500). 



tubular pharynx, which in some cases extends 

 almost to the centre of the body. The two pigment 

 bands are light green in colour, and are longitu- 

 dinally disposed. A conspicuous contractile 

 vacuole is situated immediately dorsal to the 

 commencement of the pharynx. The nucleus is 

 subspherical in shape, and situated near the 

 posterior extremity. This animal is about 24 

 microns in length. 



C. erosa may be found in fresh water among 

 confervae. 



Uveila virescens Ehr. — This species is a colonial 

 protozoon. The colonies are free swimming, and 

 each is made up of numerous (from twenty to 

 seventy) individuals united together by their 

 posterior extremities to form rosette-like clusters. 

 Each zooid is pear-shaped, the part by which they 

 are united together being drawn out and stalk-like. 

 The endoplast is spherical and subcentral. Under 

 ordinary conditions it is very difficult to distinguish, 

 but according to Biitschli the application of Beal's 

 carmine at once reveals it. There are two con- 

 tractile vacuoles situated posteriorly. The lateral 

 pigment bands are yellowish-green, extending each 

 side through almost the whole length of the body. 

 About the number of flagella present there is some 

 diversity of opinion. Ehrenberg observed two, 

 Saville Kent gives two, Dujardin observed only 

 one ; I could only distinguish one. 



This animal may be found in most ponds and 



Fig. 11. — Uveila virescens ( x 500). 



ditches, rolling about in an apparently blind and 

 aimless way. 



The Anisonemidae are characterized by Saville 

 Kent as follows : " Animalcules ovate or elongate, 

 free swimming or temporarily adherent ; flagella, 



