HYDRA. 191 



4. HYDRA OLIGACTIS. 



Hab. Still waters, in England, rare ; Hackney, Ellicot ; 

 Cranmore, near Belfast, Templeton. 



" The tails of these are long, slender, and transparent, and 

 when placed before the microscope, a long straight gut may 

 plainly be distinguished passing from the body-part or 

 stomach, to an opening at the end thereof. These are rather 

 lighter-coloured than the former (H. vulgaris), and have 

 seldom more than six or eight arms, but these capable of 

 great extension." (Baker.} 



Dr. Fleming regards the above-mentioned species as 

 varieties of Hydra vulgaris; he remarks, " The reproduction 

 of this singular being by buds issuing from the sides of the 

 parent polype ; acquiring tentacula, and then falling off and 

 becoming independent individuals, or by the regeneration 

 of parts when artificially divided ; has long engaged the at- 

 tention of the curious observer. The animals may be easily 

 procured by placing a quantity of the stems of plants grow- 

 ing under water in any slow-running ditch, in a basin of 

 clean water, and in a short time the polypes will expand, and 

 exhibit themselves readily to the naked eye." And yet how 

 few have tried to see them ! 



