464 PROCEEDINGS OF SOCIETIES. 



A neio Species of Staurastrum shown. — Mr. Archer showed, 

 amongst other forms, a new species of Staurastrum, generally very 

 rare as yet, though not uncommon in Callary bog. The only other 

 place it had occurred was sparingly in Connemara. It somewhat 

 resembled St. oligacanthum, Breb., but the little tufts of spinelets at 

 the slightly prolonged angles and on upper margin would quite 

 readily distinguish it. He would reserve a description. The Con- 

 nemara and Callary forms were absolutely identical. 



Macrospores of Salvinia natans exhibited. — Dr. E. Perceval 

 Wright exhibited germinating macrospores of Salvinia natans, 

 which were the produce of plants collected in September, 1876, in 

 the Spree by Prof. E. von Martens, and kindly forwarded to Dr. 

 Wright to Koln. The macrospores began to float to the surface 

 of the water in the last week of March, and at once developed their 

 three-edged emerald green prothallium ; only within the last few 

 days (15th April) did the microspores arrive at the surface, but 

 speedily under the influence of a few days of bright sunlight did 

 their spherical cells develope the antherozoids. Just as mentioned 

 by Hofmeister and Pringsheim did the unfertilised archigoma turn 

 brown, those more lately formed and fertilised beginning to form 

 the curious scutiform leaf. Some little care and a peculiar arrange- 

 ment of the light was found necessary to bring the spring plants, 

 of which there was a numerous colony, to this stage, but should 

 these plants produce in autumn their fruits, then the experiment 

 of cultivating this interesting Rhizocarp may be regarded as suc- 

 cessfully accomplished. 



Ampliizonella violacea, Greeff", exhibited. — Mr. Archer presented 

 examples in the living state, as well as some time under Beale's 

 fluid, of AmphizoneUa violacea, GreefF, and drew attention to the 

 nucleus so readily to be detected. The strongly developed nuclear- 

 membrane and the coarsely granular nature of the "contents" 

 reminded one, Mr. Archer thought, of the nucleus in Poraminifera, 

 as figured by Schulze. It is worthy of mention that at no time 

 could Mr. Archer detect examples of this Sarcodine showing the 

 smooth-surfaced, sharply bounded envelope depicted by Greeff, but 

 this portion of the structure always showed a hazy or "fuzzy" out- 

 line, nor could he ever see the emission of finger-like pseudopodia, 

 but only hemispherical prominences, which nowhere seemed to 

 protrude through the outer envelope. 



Ilyalosphenia-form, probably Hyalosphenia (Difflugia) ligata, 

 Tatem, exhibited. — Mr. Archer further presented a single example 

 of a Hyalosphenia-form. To which of the two (or three ?) named 

 forms this might be relegated, from want of figures of one, Mr. 

 Archer felt in doubt. It best agreed with Tatem's figure of his 

 DifHugia liyata, in ,Mr. Archer's opinion better called Hyalo- 

 sphenia ligata (if that be not equivalent to Stein's form), but it 

 was just one half the size I'ecorded by the former observei*, or say 

 -^h" in length. 



