16 NATURAL HISTORY SOCIETY OF DUBLIN. 



(Breb.), and, for my part, I see no grounds sufficient to separate them 

 in a distinct genus from S. condensata, for instance ; for surely that the 

 former live on damp rocks, forming confluent gelatinous strata, and that 

 the latter inhabit pools and live more or less isolated, can hardly be ac- 

 counted such. It is true that in S. condensata and some others, self- 

 division appears to be oblique, whilst in P. endospira it is transverse. 

 But I do not venture to express this opinion without having had an 

 opportunity to examine living specimens of what I believe to be the 

 former species (P. endospira (Kiitz.) = C. endospira, et Endospira trun- 

 corum (Breb.), which I obtained in small quantity from a moist cleft in 

 a rock on the road side in the " Rocky Valley," near Bray. But I make 

 the statement with a great amount of deference ; for I am here at va- 

 riance with the original discoverer of the two forms, M. de Brebisson 

 himself, who would still consider these as forming a genus of Palmellaceae, 

 and not as belonging to the genus Spirotaenia. I submitted mounted 

 specimens of my plant to him ; and although, owing to the unavoidably 

 altered state of the plant as compared with the fresh condition, he could 

 not speak positively as to its being actually his E. truncorum, yet he 

 believed it must be. I have myself little or no doubt but that so it was. 

 But, on the other hand, I am fortified in the opinion of the actual iden- 

 tity of the genera Endospira and Spirotaenia by that of Professor De 

 Bary, who describes a species in the latter genus under the name of 

 Spirotamia muscicola, of which he quotes Palmoglcea endospira (Kiitz.) 

 = Endospira truncorum (Breb.), as synonymous, but with a note of in- 

 terrogation appended ; and this wisely, for the identity of De Bary's 

 species with tbose of De Brebisson must indeed still remain a question. 

 I should indeed be disposed to imagine that they are distinct species, 

 but, as I have indicated, belonging to the same genus ; S. muscicola is 

 apparently a larger form. To enter into the characters of the genus 

 Spirotaenia, as already known, would be alike unnecessary and beyond 

 the purpose of this communication ; they are to be found set forth, as 

 far as is known, by various writers. No reproductive process having 

 been noticed in this genus, its position indeed remains unsettled; but 

 there cannot be much doubt but that, when discovered, it will be found 

 to be by conjugation. However, the before-indicated parietal spirally- 

 wound band of endochrome abundantly separates the two forms men- 

 tioned, included in Palmoglcea by Kiitzing, from the forms I have pre- 

 viously adverted to and from those included in the fourth and fifth types 

 presently to be alluded to. There may, indeed, be some possibility that 

 likewise the form called Palmoglcea rupestris (Kiitz.), which is thus 

 spoken of — ". . . . cellulis ex substantia gonimica convoluta trans- 

 verse hyalinozonatis ;" also P. lurida, thus described — "Substantia 

 gonimica fasciae-formi sub -convoluta," may belong here; but without 

 seeing fresh specimens of the plants so named by Kiitzing, it would be 

 impossible certainly to decide. Having thus eliminated Palmoglcea Roe- 

 meriana, P. monococca, P. endospira, and P. closteridia, and possibly P. 

 rupestris and P. lurida, the remaining forms included in this genus by 

 Kiitzing probably belong to one or other of two further apparently 



