322 Mr. Harvey on a neir species o/Codium. 



Accompanying the specimen, Mr. Moore has favoured me with 

 the following note : — " My first knowledge of this plant was ob- 

 tained in October 1843, when Mr. M'Calla inclosed me a small 

 specimen, requesting my opinion of it ; on which I examined it, 

 and by return of post wrote him that he was perfectly correct in 

 supposing he had found a new species of Codium. In his letter 

 he says, ' I found this remarkable plant last year, and from its 

 habit and situation took it at first to be a sponge, but after ex- 

 amining it better, came to the conclusion that it was a Codium, 

 in which opinion I have no doubt you will agree. It grows on 

 turf-banks near or at extreme high-water mark, spreading in large 

 patches to the extent of several yards. In dry weather it loses 

 all its characters, the frond shrinking to a mere nothing, but on 

 the return of moisture it immediately gets fresh again. ^ Such 

 is M'Calla's accovint, and you will observe from it that he has 

 both the merit of discovering and ascertaining it to be a spe- 

 cies of Codium. On the 7th of December I again received fresh 

 specimens, with a view of describing it which was delayed for two 

 reasons : first, thinking I might find it noticed by some foreign 

 author ; and secondly, that it might alter its form on the approach 

 of spring, which latter has not been the case with specimens which 

 I placed on a moist spot, where they remain unchanged, though 

 they have now been under my observation upwards of three 

 months. I thought of calling it C. cucurbitinum, from the re- 

 semblance it bears to a small pickling cucumber under the glass." 



The most curious point in the history of this interesting Alga, 

 and which has suggested the specific name by which we have di- 

 stinguished it, lies in its habitat, wherein it differs altogether from 

 any hitherto recorded species of Codium., at the same time that 

 its structure is so entirely identical with that of C. tomentosum 

 and others of the genus, that it is impossible to place it in any 

 other group. All known Codia are not merely marine plants, but 

 are generally found far removed from high-water mark, and in 

 places where they are either not entirely uncovered at low water 

 or are only left bare for a very limited time, while their spongy 

 nature enables them to retain sufficient water to prevent shrivel- 

 ling. In om* C. amphibium, however, we find these peculiarities 

 of the genus singularly departed from. It can scarcely be called 

 a marine, so much as a maritime plant, if it be affected, as would 

 appear by Mr. M'Calla's statement, by the wetness or dryness of 

 the weather. Probably it grows within the limits of spring-tides, 

 but beyond the reach of the ordinary sea-level. It is moreover 

 found growing in bog-earth, and doubtless deriving from the 

 moisture of the bog a portion of its nourishment. In all these 

 respects, as before observed, it differs remarkably from any re- 

 corded species. 



