124 ZOOPHYTES. 



prominent disparities are either too slight, or the subjects too indefinite, 

 or too intricate, to admit that ready determination, finding such powerful 

 auxiliaries in other departments. 



Amidst a competent number of specimens of all different quality, oc- 

 curring also in very different places, I acknowledge myself unable to pro- 

 nounce whether the whole concentrate in one species, whether they con- 

 stitute more, or whether they consist of varieties. The distinctions among 

 them are not sufficiently prominent : neither have I discovered a single 

 specimen hitherto, which I can thoroughly identify with the Plumatella' 

 of authors. 



Thus, I can only conclude, that the reciprocal resemblance of speci- 

 mens to each other, is not so striking as at once to prove identity, though 

 enough to establish kindred. 



I believe that, on the strictest scrutiny, we should find the same want 

 of similitude, long since alluded to, as pervading both the animal and the 

 vegetable world. 



Authors affirm that there are two distinct species of the Plumatella, 

 the repots and the reptans. 



I can speak only of the former ; for if there be actually two, it has 

 not been my fortune to see both. Much is certainly due to age and posi- 

 tion. 



In general, the Plumatella repens occurs of small dimensions, for the 

 most part formed like a branch, and always as adhering to some more solid 

 substance. 



But a perfect specimen, of great luxuriance, and of ample dimensions, 

 seems to diffuse originally rather from a central point, and finally adopting 

 such a superficial figure, as the proportional vigour of the parts shall have 

 regulated. 



If this be true, considerable difference of form will ensue from the 

 vegetative power being stronger at certain points than at others. 



The finest of all specimens are seen on stones. Of these an admi- 

 rable example occurred near a ruinous mansion called Fenton Tower, in 

 the county of Haddington, about twenty-one miles east of Edinburgh, for 

 which I was indebted to that same affectionate companion of my excur- 



