422 PROCEEDINGS OF SOCIETIES. 



were attached. He remarked that, whether we accept the carpellary 

 theory or not, the pollen-grains of archisperms or gyranosperms are 

 invariably applied to the naked nucleus of the ovule, and not to a 

 stigma. 



Microscopical Structure of Spine of Golohocentrotus atratus, 

 Agassiz. — Mr. Mackintosh showed a transverse section of a spine 

 of Oolohocentrotus atratus, Agassiz, which forms a somewhat elon- 

 gate ellipse, the major being about twice as long as the minor 

 axis. When viewed under a low power the general appearance is 

 Accrocladia-like, but differs in the irregular arrangement of its 

 periodical rings, in the absence of the wide central reticulation, and 

 in its oval form ; the radiating solid lines, also, which are so strongly 

 marked a feature in Accrocladia, are ab.^ent in Golohocentrotus. 

 When examined under a higher power the centi'al part is seen to be 

 occupied by a regular network with very small interspaces, and 

 bounded by a ring of solid pillars, outside which the reticulation 

 becomes irregular, and continues so to the circumference, the largest 

 spaces being situated at the extremities of the major axis. The ex- 

 ternal edge is crenulated, the prominences forming the longitudinal 

 ribs which project on the surface. 



Navicula Jamaicensis, Grev., and a Form of Surirella fastuosa, 

 Grev., from Philippine Islands. — Rev. E. O'meara showed Navicula 

 Jamaicensis. Grreville ; also the peculiar form of Surirella fastuosa 

 described by Greville (' Quart. Journ. Micr. Sci.,' vol. x, PI. Til, 

 fig. 1). These were found in material scraped from shells brought 

 from Cebu, one of the Philippine Islands, and kindly supplied by 

 G. M. Browne, Esq., of Liverpool. 



Spores ofPreissia commutata, exhibited. — Dr. D. Moore showed 

 spores of JPreissia commutata, found by him in one of the tanks 

 in the Victoria House at the Botanic Garden, and which he was 

 momentarilj' puzzled to find in water ; but the circumstance was 

 explained by his finding the plant established hard by. 



Muscle Spindle-shaped Cells, exhibited. — Mr. B, Wills Richard- 

 son exhibited a slide containing several isolated organic muscle 

 spindle-shaped cells, slightly stained by carmine. He observed that 

 although, in almost all the cells, the nucleus of each was visible, it 

 did not appear to be so wide as represented in the organic muscle- 

 cells as illustrated in many works on histology. 



Anew Species of Staurastrum, exhibited. — Mr. Archer showed a 

 minute new species of Staurastrum with its zygospore ; but without 

 a complete techninal description, if not a figure, further reference 

 be of no use. 



Specimens of Isotoma arbor ea, remarkable for the vast quantities 

 in which it occurred, exhibited. — Mr. A. G. More exhibited a minute 

 creature, evidently belonging to the Collembola of Lubbock, which 

 had been found in amazing quantities beneath the floor of a green- 

 house ; they were removed by thousands. 



Dr. E. P. Wright, on a casual examination, seemed to think 

 they were specimens, in almost all stages __of coloration, of Isotoma 

 arborea. 



