ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 
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5. Aracbnida. 
Adaptive Modification of Spider’s Web. — Henry E. Crampton 
(. Proc . Amer. Soc. Zool. in Anal. Record , 1922, 23, 130). Along the 
railroad through the jungles of southern Siam, the telegraph wires 
provide spaces of varying width which are used as a basis for the webs 
of Argiopid spiders, probably of the genus Nephila. Full-sized webs 
are made where the intervals are suitable. Where the interspaces are 
less than the diameter of a normal web, the spiders modify the 
structures by omitting an upper sector of greater or less extent, making 
an effective adjustment. J. A. T. 
Crustacea. 
Nutrition in Phyllopods. — 0. Lundblad (Arkiv.f. Zool., 1921, 13, 
No. 16, 1-114, 1 pi., 7 figs.). A detailed study of the modes of feeding 
in Phyllopod types. The genus Tanymastix is a typical plankton- 
feeder ; Limnadia is a mud-eater ; Lepidurus is mainly carnivorous, but 
to a slight extent a rnud-eater. There are adaptations to these different 
modes, but the mouth-parts are all referable to the same general type. 
The bending down of the head against the ventral surface of the body 
is characteristic. The spines and setas of the endites of the appendages 
and of the ventral groove are functionally important. J. A. T. 
Annulata. 
Earthworm’s Reactions to Light. — Walter N. Hess (Proc. Amer. 
Soc. Zool. in Anat. Record , 1922, 23, 122-3). Earthworms, which are 
negative to light of ordinary intensity, become positive, in keeping with 
their nocturnal habits, when the light is greatly diminished. If, how- 
ever, the brain is removed either by a dorsal incision or by the removal 
of the first three anterior segments, they no longer react negatively to 
ordinary illumination, but become strongly positive. If six or more of 
the anterior segments of Lumbricus terrestris are removed, the worms 
are still positive. Similar results were obtained with Allolobophorci 
fcetida when as many as forty anterior segments were removed. These 
results show that the brain of the earthworm is not necessary for re- 
actions to light and photic orientation. They indicate that earthworms 
are more sensitive to light when the brain and the photo-receptors at 
the anterior end are functional, than they are when these structures are 
not functional. This accounts for the fact that, while normal worms 
are positive only in very weak light, specimens with the brain removed 
are positive in strong light. J. A. T. 
Bifurcation in Embryos of Tubifex. — Paul S. Welch (Biol. 
Bulletin , 1921, 41, 188-201). Bifurcation is frequent and varied in 
embryos of Tubifex tubifex. In each cocoon there are 1-17 ova. The 
emergence of the young worms is through two opposite apertures. 
Approximately 20 p.c. of the cocoons contained bifurcate embryos. 
Both ends of the body may be affected, in simple or compound form. 
In more than 4,000 recently emerged worms only 10 bifid forms were 
found. Any departure from normal body form involving increase in 
