Dublin Microscopical Club. 207 



increase to the size of Y by September, it might then be 

 45 millim. by 56 millim, by next June. It is also probable 

 that in confinement the young Carcini do not develop exactly 

 with the same rapidity as they would in their natural haunts. 

 Doubtless the environment, the temperature, and possibly 

 also the quantity of water and the amount and nature of the 

 food available will all have their influence on the rapidity of 

 growth. 



PlIOCEEDINGS OF LEARNED SOCIETIES. 



DUBLIN MICROSCOPICAL CLUB. 



October 18, 1883. 



Camijanularia verticillata. — Prof. Macintosh exhibited a specimen 

 of Campanulnria verticillata differing from the type of the species in 

 that the caUcles have even rims instead of denticulate ones. The 

 specimen was dredged in about 12 fathoms water off Greystones. 



Sections of Chiton. — Prof. Haddou exhibited transverse sections of 

 Chiton (Trachydermon) ruber, showing the presence of an oviduct, 

 contrary to W. H. Dall's statement, the so-called " ovarian fenestras " 

 being merely the folded lips of the external openings of the oviducts. 



Spore-bearing Nostoc. — Prof. M'Nab exhibited a portion of an 

 unidentified Nostoc (which had presented itself in one of the conser- 

 vatories at Glasnevin Botanic Gardens) in a fertile condition, that 

 is to say, showing spores ; these occurred in chains of several in a 

 continuous row, elliptic and notably wider than the ordinary joints 

 of the filaments, and seemingly showed no very noticeable relative 

 distribution as regards the hetcrocysts. This is the second fertile 

 Nostoc which has been noticed in this country, though several species 

 have been foimd in that condition by Dr. Bornet, who has been so 

 successfully studying the group. 



Characters of the Hairs of Acanthus sj)inosus. — Mr. Greenwood 

 Pirn showed hairs from the anthers of Acanthus spinosus. These 

 were of two kinds — one short and straight, forming a thick close 

 brush along the edges of the suture of the anthers ; the other longer 

 and more flexuous, and situated on the dorsal portion of the antheis. 

 The short straight hairs had their surfaces curiously reticulated into 

 labyrinthiform folds of every conceivable shape, whilst the dorsal 

 hairs were only longitudinally striate. The position of the latter 

 differed according as they Avere growing on one of the posterior 

 pairs of stamens, whose anthers are in apposition, or on the ante- 

 rior pair, which are free throughout. 



