24:2 NATURAL HISTORY. 



pelvic bones are to be found embedded in the flesh, like the clavicles of the 

 tiger, useless save as a clue. 



" Now I have taken up my foil share of your time, and have but half gone 

 through my subject. The links between the Eodents, Proboscidea, Ungulata, 

 and Ruminantia must remain over for some future occasion if the subject be 

 deemed of sufficient interest to call for more of it." 



Pollen Grains. 



Dr. Kirtikar exhibited under the microscope the pollen grains of the Rose 

 hibiscus, Canna indica, Calotropis gigans, Calophyllum inophyllum, Pandanus 

 odoratissimus, Amarjllis, Garuga pinnata, &c, and went on to explain what 

 pollen was. He said it was commonly a yellow powder, sometimes gritty, often 

 impalpable, and was the product of the male portion of the reproductive 

 organs of flowering plants or phanerogams called stamens. It formed an 

 essantial element in the process of fertilization or impregnation of the ovule. 

 The pcllen of the male organs or stamens and the ovule of the female 

 organs or pistil by themselves, i. e., alone and untouched or unaffected 

 by each other, were powerless in the propagation of the species to 

 which they belonged. The pollen had to come into contact, either directly or 

 indirectly, by being carried from stamens to stigma, from flower to flower, by 

 the busy bee and brilliantly coloured butterflies and moths, or by simple 

 currents of air, winds, and storms. Mr. Blockley's researches have shown that 

 hay fever was caused by the migration of pollen grains of grasses, lilies, 

 roses, and other plants. Professor Otto Thome, of Cologne, the lecturer said, 

 bad stated that in forests consisting of those trees which bore catkins, immense 

 clouds of pollen were seen floating in air, at the time of pollination, which 

 were sometimes carried to the earth by showers of rain and there formed the 

 so-called sulphur-rain. Special contrivances, Dr. Kirtikar said, existed in 

 water-plants for the utilization of pollen grains. Submerged plants always 

 threw their flower-stalks above the surface of water, as in Trapa sagitta 

 and water-lily. "Vallisneria spiralis however had a remarkable mode 

 of fecundation. The male flowers containing the pollen were seated 

 on very short pedicels at the base of the leaves, often several feet below 

 the surface of the water. The female flowers on the contrary had very long 

 pedicels, which at a particular time became greatly elongated and raised the 

 flower to the surface of the water. The male flowers next became detached 

 from their pedicels, rose to the surf ace, were floated among the female flowers, 

 and thus fertilized the ovule. After this had been accomplished — and this is 

 the most remarkable part of the whole process — the female flower coiled up 

 spirally and the fruit ripened beneath the water. The subject of cross-fertili- 

 zation which Darwin had so ably followed, the lecturer said, was a study by 

 itself vast and interesting, whereby crossing between different flowers of the 

 same plant, or between flowers on different plants of the same species, was 

 explained. 



Pollen, he said, was discharged generally at the time of the opening of the 

 flower, i. e., from the time it completed its bud-state to the time it expanded. 

 The process of pollen-discharge however, he said, might and did continue 

 for some time after the flower had fully opened, but that this happened 



