OBSERVATIONS OF SIR J. DALYELL. 113 



I was unable to ascertain their origin ; they have re- 

 mained some days in activity, and then vanished with- 

 out leaving the slightest trace behind. No species 

 could be preserved with facility, though but for a 

 short period; they did not seem referable to any 

 particular time or subject ; everything regarding them 

 was wrapped in mystery. 



While a number of vigorous Hydrse still terminated 

 the extremities of a specimen of Tubularia (Euden- 

 drium] ramosa, I suspended various specimens by silk 

 threads in vessels of sea-water. Several white specks 

 among the twigs issuing from the branches then 

 became perceptible by the naked eye, which, under 

 the microscope, proved to be solid pear-like sub- 

 stances, of a bluish-grey colour. Thence I proposed 

 to call them Py rules. Thinking little of the matter at 

 the moment, I concluded they might be regenerating 

 Hydrae, as not unusual with different zoophytes ; but 

 my attention was soon arrested by the position of 

 some, as if seated on the long neck of the living 

 Hydra. I could not doubt but that one neck sus- 

 tained three (PI. II. fig. 2, b), and that elsewhere a 

 cluster of four appeared at the extremity of a twig, 

 then vacant, of a polyp. Further investigation ascer- 

 tained the following facts : 



Minute pear-shaped bodies (Pyrula), as above spe- 

 cified, are dispersed on the stalk of different parts of 

 the zoophyte at considerable intervals; sometimes 

 three are together, sometimes two opposite to each 

 other, or only one terminates a twig where it might 

 be readily supposed a regenerating Hydra. Each 

 Pyrulum is affixed by its own distinct pedicle, which 



