Astasiaea.] infusoeial animalcules. 191 



less at the extremities. This is one of the most beautiful animalculea 

 I have seen under the microscope ; its graceful form when swimming, 

 its bright red eye, the curious forms it assumes when stationary, and 

 its remai'kable appearance when undergoing self- division, aU com- 

 bine to render it worthy of observation. Group 78 shows the normal 

 form of this creature ; the figure to the right, the same bent and 

 contracted; and the lower, another undergoing longitudinal self- 

 division. Found both in fresh and brackish water. Length 1-5 70th 

 to l-210th. 



EuGLENA rostrata. Body elongated and conical, vrith the hinder part 

 gradually attenuated into the tail, which is very short. Head slightly 

 bent, like a beak ; colour green. Found amongst Oscillatoria and 

 Bacillaria. Length about 1 -500th. 



E. ovum. — Body ovate green, with a very short hyaline caudal 

 prolongation; and a large double circular gland. Size 1 -1560th. 

 Found at BerLui. 



E. geniculata. (D.) — Body green elongated, cylindrical, flexible, 

 but not very contractile, movement slow, taU tapering, and at an 

 angle with the body, hence the name. Length l-208th to 1-I75th. 



This large Exujlena is remarkable by its elongated form, by its 

 diameter being nearly equal to its length, without the bulging of E. 

 viriclis, and by its articulated tail. 



E. ohscura, (D.) — Body thick, oblong, distended and obtuse poste- 

 riorly ; of very variable form, clearer, and of a red tint anteriorly, 

 eye-speck reddish black ; filament half as long again as the body. 

 Length 1 -870th. 



Genus CHLOEOGOisrnr&r. The Astasia with a double proboscis. — 

 This genus comprises those members of the family Astasiaea which 

 are provided with an eye, tail, and double thread-like proboscis ; 

 thek motion in swimming is free, the creature not being attached by 

 means of a pedicle or foot-stalk. The only known species is of a 

 very beautiful green colour, and has numerous transparent vesicles 

 within it, which are apparently subservient to the purpose of nutri- 

 tion, although this fact has not been determined by the imbibition of 

 coloured food. A faint, clear, glandular body (the male generative 

 system) is perceptible in the centre of the animalcule, the female 

 being represented by the mass of green ova, which confers the colour 



