and ;S^. Jenneri. The former is a slender form, with large coils or 

 spirals, and, the filaments being intertwined or doubled on them- 

 selves, large, continually changing openings or intervals occur, 

 giving, as they mutually and somewhat quickly twist and untwist, 

 a very graceful appearance. The latter is a thicker and stouter 

 filament of short coils, and when intertwined they lie in closely, 

 curve to curve, leaving no interspaces, the result being a rope or 

 plait-like appearance. These occur in greater or less strata, at 

 the bottoms of pools, and sometimes rise to the surface in little 

 masses, like Oscillatoriae buoyed up by bubbles. 



Mr. Crowe showed sections of fossil tooth of shark and fossil 

 palm. 



Dr. John Barker likewise showed the conjugated state of a 

 minute Cymbella, the four valves of the original pair of conjugat- 

 ing frustules lying closely applied to the pair of yovmg frustules, 

 these lying parallel and surrounded by the former, the whole 

 involved in a mucous envelope. 



Dr. Moore showed examples of the alga JBotryococcus Braunii, 

 which occurred in long sheets, of some yards in length, floating 

 on the surface of Lough Bray, so as to become a conspicuous 

 object. In this plant the clusters of green cells are imbedded in 

 a colourless mucous matrix, and sometimes such clusters remain 

 united by strings of this mucous investment. 



Mr. Archer mentioned that Botryococcus Bratinii was not 

 seemingly an uncommon alga in moor pools, sometimes coating 

 submerged sedges and the like with a greyish-green stratum, 

 sometimes, however, suspended in the water in streaks, and often 

 isolated. It passes through a red condition. He had, however, 

 never seen it in anything like the masses described by Dr. Moore. 

 More than once, when a single group or family of this alga, 

 from gatherings kept for some time in the house, had turned up 

 under a low power of the microscope, he had been to some extent 

 deceived by the way in which it resembles some radiolarian 

 rhizopod, strange as it may seem. The mucous matrix containing 

 the families of cells seems not unfrequently to give off rather 

 long, filiform, prolongations, which stand out more or less radiantly, 

 looking not unlike pseudopodia, and these are undoubted rhizo- 

 poda containing chlorophyll. It might, indeed, be a good example 

 of two objects, with no aflinity in any respect to each other, still 

 superficially simulating one another. 



Mr. B. Wills Richardson exhibited some very beautiful sections 

 of hempseed calculi, cut for him by Mr. Charles Baker, of Holborn, 

 London. About 600 specimens of this description of calculus 

 were passed by the patient — a gentleman advanced in life — in the 

 space of a few months. Several being facetted, led him at first 

 to suppose that they came from the prostate gland ; but analysis 

 proved their composition to be oxalate of lime, with traces of 

 lithic acid. 



Rev. E. O'Meara referred to two packages of material kindly 

 supplied to him by Sir Leopold McClintock. One was raised 



