Royal Irish Academy, 97 



Were collected at Torquay, and we subjoin the following extracts 

 from a letter by that distinguished aigologist, which accompanied 

 the specimens. " I have (she says,) sent you some plants of Lami- 

 naria digitatay exhibiting the singular mode by which the plants of 

 this genus reproduce their frond from time to time, and I believe 

 many of them annually. You will observe one of them beginning to 

 form a new frond at the base of the old one, and between it and the 

 stem, the other is further advanced and is preparing to throw off and 

 take the place of its predecessor. In a few weeks the new one would 

 have attained a much larger size, and so on, until at length the root 

 gives way, unable to support the weight. 1 beg to observe that I do 

 not claim the merit of being the discoverer of the renewing power 

 possessed by these plants, that being noticed by Dr. Greville in his 

 AlgcE Britannicce; but a long residence by the sea in favourable si- 

 tuations has enabled me to trace their progress from the earliest period 

 of their existence to their final decay, and therefore I feel competent 

 to speak with confidence upon the subject. 1 am not certain that 

 the reproduction takes place annually, although I think it probably 

 does so from the clean and fresh appearance of the plants in the 

 months of June and July, and the immense quantity of fragments 

 cast on the shore in April and May, and which are carted ofl' for ma- 

 nure. The same mode of growth prevails also in Laminaria bulbosa 

 and saccharina, but it is impossible to preserve the former from its 

 great size." 



Read a notice on Succinea amphibia, and its varieties. By Mr. 

 Daniel Cooper, A.L.S. 



Read likewise a paper by Edwin J. Quekett, Esq., F.L.S., entitled 

 *' Some observations on the varieties of growth of plants belonging to 

 the genus Chara of Hooker." 



Sir William Hooker has in the British Flora expressed an opinion 

 that our British Chara may be reduced to two species, namely, C. 

 vulgaris andjlexilisj the former including all those with opake stems, 

 and the latter those with pellucid stems. Mr. Quekett*s observa- 

 tions go not only to prove that this opinion is correct, but that even 

 the vulgaris andjlexilis are themselves but different states of one and 

 the same species ; for that plants of Chara hispida which he had 

 grown in ajar exhibited both states in the same stem, some branches 

 being extremely simple and pellucid like Nitella, while others, as well 

 as the main, had an envelope of spiral tubes, and were incrusted, 

 striated and opake, partaking of the characteristics of vulgaris and 

 hispida. The incrusting material consisting of carbonate of lime, 

 Mr. Quekett supposes to be an accidental circumstance, depending 

 upon the presence of that substance in the water, and that in the pro- 

 cess of appropriation of the carbonic acid by the plant, the carbonate 

 of lime becomes precipitated upon the stems in the form of minute 

 crystals. 



ROYAL IRISH ACADEMY. 

 [Continued from vol. xi. p. 136.] 

 Februarv 13. — Dr. Gregory read a paper, entitled, "Examination 

 Phil. Mag, S. 3. Vol. 12. No. 71. Suppl. Jan, 1838. O 



