A HISTORY OF SURREY pasture land from a hilltop would produce ' shrimps,' or any other aquatic organisms, was an expectation that required some robustness of faith even in the zoologists of the party. If it inspired others with incredulous amusement they could scarcely be blamed. On August 21 some of the earth was placed in water. On the thirtieth it proved to have Ostrac6da alive in it and a Chirocephalus a quarter of an inch long. The next day a second Chirocephalus was perceived of slightly smaller size. Both of these must have been born some days earlier. On September 6 the rest of the earth was put into water, and on the eleventh minute animals were found to be moving about, two of which appeared on the following day to be microscopic Chirocephali. It was pleasant to watch these creatures, and the preliminary to watching them was itself interesting. So artfully are they adapted chameleon-like to their surroundings, that even when full-grown in a small bowl under a good reading-glass they are not at once discoverable. When found they are seen sometimes to make rapid darts and sudden evolutions, more often to glide serenely along, or at will simply to hover in the water, with their eleven pairs of leaf-like limbs all the while in constant motion. The development of the sexual distinctions is also of interest. In the male the prehensile second antennas and the digitate frontal processes are highly characteristic. The full-grown female is quite as easily dis- tinguishable by her long projecting marsupium. In this, at least while not filled with eggs, the glandular structure which supplies the egg- shells appears to be in ceaseless activity. Difficult as it is to discriminate the animal from the mud over which it is swimming, it is far from being mud-coloured. It has a general tint of transparent greenish-brown, with blue on the back along the region of the heart ; the large lateral eyes show red under a favourable light ; the small median eye-spot is dark, the marsupial gland brown, the caudal furca bright red. The back is almost always downwards. The colours vanish in spirit, except that the marsupial gland retains some of its brown hue, and the eyes appear as black under a white coating. In the chilly part of the autumn the specimens which had not been put into spirit buried themselves in the earth, and have not reappeared. Whether under any circum- stances they would have done so I cannot say for certain. It was eminently improbable that they would do so under the conditions they actually experienced, for during the winter the water was allowed to evaporate without being replenished, and the earth became by degrees a hard mass in the bowls. On April 9, 1901, water was again poured upon it, with the result that on the twentieth of the month a Chiro- cephalus about a tenth of an inch long was descried, and soon afterwards a second made its appearance. At the time of writing, May 10, the specimens are swimming about in a lively manner, one of them showing the characters of a female. Scores of Ostracoda are displaying an even greater vivacity, and if so much energy cannot be sustained without animal food, it is perhaps these minute creatures which keep down the phyllopod population by massacring their defenceless young. The 192
Page:VCH Surrey 1.djvu/234
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