ZOOLOGY AND BOTANY, MICllOSCOPY, ETC. 183 



How Silkworms Eat.* — ^H. Jordan points out that silkworms always 

 begin at the margin of the leaf, which they are wont to hold firm with 

 their front legs. The head and the front of the trunk describe semi- 

 circular movements It is not that the mandibles directly cut, they 

 grip ; and a fragment is tugged at by a backward movement of the head. 

 But the help of the upper and lower lips is needed ; they move approxi- 

 mately at right angles to the long axis of the silkworm, and shut down 

 upon the leaf-margin, pressing it away from the fragment gripped by 

 the mandibles. The separation of the fragment is effected. 



5. Arachnida. 



Structure of Ixodes reduvius.t — Erik Nordenskiold continues his 

 study of this tick. He deals with the skin and its glands, the changes 

 of the skin during histolysis, the alimentary system and its changes during 

 development and in the course of its functioning, the cutaneous respira- 

 tion of the hexapod larva3 and the tracheal system which arises after the 

 first ecdysis, the vascular system, the musculature and the using up of 

 the body of the female in the service of reproduction, for almost all the 

 somatic tissues make their contribution to the equipment of the ova. 



Araneida and Phalangida of Clare Island. |— Denis R. Pack Beres- 

 ford gives a list of 108 species of spiders, which do not differ materially 

 from those of the adjoining mainland. It has to be remembered that 

 although spiders have no wings, " their means of dispersal are almost, if 

 not quite, as great as if they had ; for most species are aeronauts in their 

 youth, while many of the smaller species are probably carried about by 

 the wind at all times." The question then what species of spiders we 

 are likely to find in a given area resolves itself very much into a question 

 of suitable habitat, or what kinds are likely to survive and increase under 

 the conditions in which they may find themselves. Three species have 

 not previously been taken in Ireland — Pedanostethus anmdinetis Camb., 

 Metopobactrus prominuJus Camb., and the very rare DipJorpphuJm casta- 

 neipes Simon. The author also records seven Phalangida from Clare 

 Island. 



Eye of Pantopoda.§ — I wan Sokolow has studied the structure of 

 the eye in Nymphon stroemii, N. longitarse, Chsetoniimphon spinosum, 

 Pijcnogonam Uttorale, Ammothea fibidifpra, and Phoxichilus vulgaris. 

 The chief peculiarities are the following. 1. The lens is differentiated 

 into two parts, the lower of which shows a deep groove on its internal 

 surface. '2. The hypodermis cells are inclined to the two sides of the 

 eye, and leave along the lens-groove a free space for the ends of the pig- 

 ment cells, o. The pigment cells are long drawn out, and form a proper 

 pigment-layer by their basal ends only : they are fastened distally to the 

 lens-groove. 4. The tapetum is formed from the thinned proximal por- 

 tions of the pigment cells. 5. The distal ends of the retina-cells form 



* Biol. Centralbl., xsxl. (1911) pp. 111-4 (3 figs.). 

 t Zool. Jahrb., xxxii. (1911) pp. 77-106 (2 pis. and 3 figs). 

 X Proc. R. Irish Acad., xxxi. (1911) Clare Island Survey, pts. 35-6, pp. 1-8, 

 and 1-2. 



§ Zeitschr. wiss. Zool., xcviii. (1911) pp. 339-80 (2 pis. and 1 fig.). 



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