Dublin Microscopical Club. 339 



of 1000 feet " (1859), was GlceotricUa natans, Thurct. No. 20, " iV. 

 2wradoxum" might perhaps be a distinct thiug ; hut the specimen 

 found " ad muscos dense ca3spitosos, juxta riviilos pr. Pedra Souague 

 in ipso Proesidio, 1857," was both sterile and young; and if Dr, 

 Pornet had found such in France he would not have hesitated to 

 refer it to Nostoc elUpsosporum. No. 21, " hab. ad rupes viilcani 

 prope Cabondo, tempore pluvio, Feb. 1857," was no doubt Nostoc 

 commune ; and to this species might also be referred No. 22, found 

 " ad rupes." 



Cystoliths in Leaves of Gymnostachum (md Fittonia. — Mr. Green- 

 wood Pirn showed sections of the leaves of Gymnostachum and Fit- 

 tonia, in which were remarkable cystoliths, hitherto unrecorded 

 from these genera, although met with in other allied Acanthacese, 

 These bodies were rounded oblong in shape, slightly tubercular, and 

 apparently destitute of any suspensor (as in Ficus elastica), and of 

 cellulose basis, as dilute nitric acid dissolved them almost entirely, 

 leaving a scarcely perceptible residuum. They were much larger 

 than the cells of the parenchyma of the leaf, in which they occupy 

 intercellular spaces. There appeared but little, if any, specific dis- 

 tinction between the leaves of Gymnostachum Verscliaffdtii axi^ Fit- 

 tonia argyroneura, the two species exhibited. Subsequent exami- 

 nation of some half dozen of the forms of Acanthace?e showed very 

 similar bodies in all but one genus, Aphelandra. The other genera 

 in which Mr. Pirn observed these were Justicia, Thyrsacanthus, and 

 Adhatoda, those of the last named being longer and more clavate 

 than in the other forms. 



Dr. Zimmermann's Preparations of Fungi. — Dr. M'Nab showed 

 some examples of Dr. Zimmermann's preparations of minute fungi, 

 remarkable for the skill arrived at and success attained in preserv- 

 ing these delicate objects. 



Cosmarium isthmochondrum,l:s ordat., new to Ireland. — Mr. Archer 

 showed Cosmarium istlimochondrum, Nordst., from Connemara, new 

 to Ireland. This was, in unison with Nordstedt's experience in 

 Sweden, found in company with another rare species, Cosmarium 

 quinarium, Lundell ; and, if carelessly viewed, the two species might 

 be confounded, as Nordstedt remarks. But they are very distinct 

 things ; indeed, once their differences are grasped, they could readily 

 be distinguished, even under the lowest power. The conspicuous 

 and rather large and prominent papilla immediately over the isthmus 

 on each front surface of each semicell is a marked feature of the form 

 in question (Cosmarium isthmochondrum), and one very readily seen. 

 There could be no doubt that both the forms entirely agree with 

 those of Sweden. They are both very rare in Ireland. As yet C. 

 quinarium has not turned up in the east ; it extremely sparingly 

 presents itself in Westmeath ; but now and again in spots a somewhat 

 copious gathering may be made in Connemara ; it is more rare in 

 the south-west. 



