Astasiaea.] infusorial animalcules. 185 



attacli themselves, it'is but for a time, and no appearance of germi- 

 nation ensues. The closest similarity exists in the case of the 

 Chlamidomonas pulnsc/dus, (Bisehm viridis Duj.), and in a less 

 degi'ee in the Euglence. (See Part I., page 46.) 



Genus Astasia. — The members of this genus are characterized by 

 their being free (not attached by a pedicle), and being furnished 

 with a long or short tail, but no eyes. A. pusilla is the only 

 species in which digestive cells have been clearly seen. Ova are 

 perceptible in A. haematodes, and probably exist in the three other 

 species ; a locomotive organ in the form of a thread-Hke proboscis 

 exists in A. 2nmlla. 



The immense numbers in wliich these Infusoria are developed in a 

 few days, and the blood red-colour they impart, have not unfre- 

 quently been the cause of considerable alarm and anxiety to persons 

 residing in the vicinity of the waters wherein they are found. 



A. haem(dodi'-s. The llood-lilce Astami. — Body fusiform, or spindle- 

 shaped, when extended ; tail \Grj short, body green at first, after- 

 wards of a blood-red colour. Group 68 rei)resents one creature 

 extended, and another contracted. (Hampstead). Length l-380th. 



A. flavicans. — Body extensible, cone-shaped, approaching cylin- 

 drical, and rounded at the foremost extremity. Tail very short and 

 blunt ; ovai'ia of a ycUo-svdsh coloui\ Found in yeUow ditch water. 

 Length about 1 -430th. 



A. pusilla. — Body extensible, cone-shaped, swelling out, and 

 rounded at the fore extremity ; tail very short and pointed, colour- 

 less. Group 69 represents two of them magnified. 



Ehi'enberg remarks, they are often so abundant, that thousands, 

 perhaps millions, of these creatures are sometimes contained in the 

 hollow of a Avatch-glass, and that they rise up and form a stratum 

 on the surface of the water. They might be mistaken for the young 

 of the A. flavicans , but that the vesicles within them, which appear 

 to be digestive cells, are larger than those in that species, which is 

 moreover ■ndthout proboscis. As soon as a little colouring matter 

 was thrown into the water, an evident current was observed near the 

 fore part of the creature; and by this means, in 1833, the thread- 

 like proboscis, which is about half the length of the body, was first 

 perceived. Sometimes the entii'e creature appeared to glisten. 

 Should this species, upon closer inspection, be found to be ciliated, 







