PROGKESS OF MICROSCOPICAL SCIENCE. 31 



bear so much resemblance to tliat of a foraminiferous test as the legs 

 of a table to those of a quadruped ; while, if such be the grounds on 

 which geological inferences are established, the sooner they are aban- 

 doned the better for geology, the worse for sensationalism ! The con- 

 tents of this letter are open to no controversy. My knowledge of 

 foraminiferous structure has been obtained step by step, beginning 

 with the recent and then going to the fossilized forms, making and 

 mounting my own sections, from which afterward my illustrations and 

 descriptions have been taken. If others who have pursued a similar 

 course of instruction differ from me in what I have above stated, the 

 question can only be decided by a third party, not on verbal arguments 

 alone, but on a comparison of the actual specimens, as prolonged dis- 

 putation, in matters of opinion, soon disgusts everybody but the com- 

 batants, and can end in nothing but a fearful waste of time that might 

 be better employed." 



The Air-cells in Limnanthemum. — Dr. T. G. Hunt contributes a 

 short account of the above to a recent number of the ' American 

 Naturalist.' He says that in the leaf of Limnanthemum lacunosum, or 

 floating-heart, may be demonstrated multitudes of peculiar stellate 

 bodies, apparently like those found in the stem of Nuphar. The 

 whole interior of the leaf is studded with them. There are no ordi- 

 nary large air-spaces so often found in other floating-leaves, but all 

 through the parenchyma these curious bodies are ii'regularly scattered. 

 They vary in size and also in the number of rays given oft' by each. 

 These rays are smooth and not echinulate like those in Nuphar. In 

 the field of a f lens he has counted hundreds at one view. Under 

 the polarizing binocular microscope, proi^erly illuminated, they are 

 revealed with startling distinctness and beauty. It is nearest the 

 under epidermis that they are located, and the best view therefore is 

 obtained from beneath. Their true physiological significance is not 

 doubtful. In the natural condition they contain air, and the floating- 

 heart rides securely on the surface of the lake, buoyed up by innmne- 

 rable life-preservers which are not likely to shift out of place. The 

 veins in the leaf are present, of course, but are comparatively rudi- 

 mentary. The vascular bundles are faintly marked, and only a few 

 delicate supporting cells line their margins ; thus giving another 

 example of nature's economy, for where strongly developed organs are 

 not necessary there we do not find them. 



Mr. W. Archer on the so-called Ague-plant. — It seems that the 

 editor of ' Grevillea ' sent some of this plant to Mr. Archer, of Dublin, 

 who has explained its nature very distinctly by showing that it is 

 simply Hydrogastrum. He says (in ' Grevillea,' May), " On reading over 

 the more recent description of the ' Ague-plant,' communicated by Dr. 

 Bartlett to the ' Chicago Society of Physicians and Surgeons,'* one sees 

 how fairly it tallies with the known characters of Hydrogastrum,| but 

 it is undoubtedly surprising how he and the American observers of 

 the Society referred to (loc. cit.) failed to perceive the identity of the 



* See 'Grevillea,' No. 21, March, 1874, p. 142. 



t See also Parfitt iu 'Grevillea,' No. 7, January, 1873, p. 103. 



VOL. XII. D 



