36 PROCEEDINGS OF SOCIETIES. 



commonly occur on all the Irish mountains: — Nebria brevicollis and 

 nivalis (of the latter, both the red- and the black-legged varieties), 

 Carabus catenulatus, Byrrhus pilula, Othius melanoeephalus, Homalota 

 bolitochara, &c. In the plantations about Newcastle Cyphon deflexi- 

 collis and C. griseus were abundant. A single specimen only of Cleonus 

 sulcirostris occurred upon the sands below, where Mr. Furlong had 

 previously found the species pretty numerous. The other Coleoptera 

 observed there were mostly such as are common on the sand-hills of our 

 coast, except one {Byrrhus dorsalis), which is an addition to the Irish 

 Fauna. Early in August the sands were traversed by hosts of the larvae 

 of Coccinellae ; later in the season these had taken up their quarters on 

 the thistles, where many of them fell victims to the attacks of the active 

 Ichneumonidae, which were continually running over those plants. 



FRIDAY EVENING, JANUARY 16, 1857. 

 E. Ball, LL.D., President, in the Chair. 



This meeting was specially directed to subjects connected with the 

 Microscope. 



The Minutes of last General Meeting having been read, were agreed 

 to, and signed by the Chairman ; after which 



"Wm. Archek, Esq., read the following — 



CATALOGUE OF DESMTDIACEJE. 



The following list of the Desmidiaceae which I have found about the 

 "Feather-bed" and "Seechon" mountains, near Dublin, is not, of 

 course, assumed to be a complete list. It is, however, a perfect one 

 (with, perhaps, the exception of the genus Pediastrum) of the species I 

 have met with in my limited experience ; and I have no doubt but sub- 

 sequent search will very much extend it. I have ventured to append to 

 each species an opinion as to its frequency or rarity, which, I need 

 hardly state, is to be interpreted as the result of my own experience only 

 in a limited district. ' Some of those I have marked as rare may ulti- 

 mately prove frequent. I am inclined to corroborate an observation 

 made in Mr. Ealfs' beautiful " Monograph," as to the non- occurrence of 

 the same species in the same pools from year to year. For instance, in 

 the year 1855, a certain pool produced Didymoprium Borreri in great 

 abundance. During 1856 I could not find a single specimen of that spe- 

 cies ; but its place was taken by a considerably less abundant develop- 

 ment of Hyalotheca mucosa. 



The "swarming" movement of the contents of the fronds of many 

 species I have found to be very frequent. Mr. Half ssuggests these 

 moving granules may be analogous to the zoospores of other algae, and 

 perform a similar function. The movement resembles somewhat that 

 observable in the fovilla of pollen. If these granules be zoospores, and 

 even a moderate proportion of the same should prove productive, should 



