40 SUMMARY OF CUERENT RLSEAECHES RELATING TO 



of chromatin from the polymorphic nuclei. The latter are to be re- 

 garded as the result of the coalescence of single nuclei, which, again, are 

 due to nuclear fragmentation. 



[ Arthropcda. 



Comparative Embryological Studies on Insects and Spiders.*— 

 The late V. Faussek left a number of almost completed studies on the 

 development of cockroach and spiders, and the general problems of the 

 ccelom and of embryonic excretion. The first deals with the necessity 

 for elimination-processes in the development of the embryo. The second, 

 dealing with the embryonic cockroach in particular, defends the hypo- 

 thesis that the coelomic vesicles are temporary organs for the accumula- 

 tion of the embryonic excretory products. Thirdly, the excretion of the 

 developing spider is considered. The rectal vesicle, which has fluid 

 contents to start with, becomes crowded with guanin granules. The 

 fatty body of the developing cockroach becomes at a very early stage 

 the seat of the deposition of salts of urea. It is suggested that the 

 macrocytes in the developing spider may have an analogous role. There 

 is an interesting comparative survey of the process of excretion in 

 Invertebrates. 



c. Insecta. 



Habits cf Aphaenogaster sardca Mayr.f— A. H. Krause-Heldrun- 

 gen gives an interesting account of this Mediterranean ant, which he 

 studied in Sardinia. It shows very little constructive industry, but uses 

 holes in the ground. It does not store, and it has no "guests." The 

 society usually consists of ?>00-1000 individuals : the males have not 

 been found. ' Both in summer and winter the members of the colony 

 huddle together in a ball with the eggs, larva?, and pup» in the middle, 

 held by the mandibles and tard of the adults, which are similarly inter- 

 locked with one another. In winter the ball is very slow to relax ; in 

 summer it is made and unmade several times a day. 



Brain of the Ant.| — H. Pietschker gives a minute account of the 

 brain of the ant, comparing the degree of development of the various 

 parts in queens, males, and workers. He shows, wter alia, that the size 

 of the " mushroom-shaped body " is not by itself an index to the degree 

 of mental capacity. There are other important parts, such as the anten- 

 nary swelHngs and the optic lobes, which count for much. The author 

 has discovered at least two new nerves from the brain. 



Structure of Bee.§ — Enoch Zander has written a reliable book on the 

 structure of the hive-bee, which he describes in generally intelligible 

 language, and illustrates with photographs and diagrams. 



Sense-organs of Eee.— Charles Janet describes |1 a chordotonal organ 

 at the articulation of each of the antennae in the bee, and between the 

 two bases an antennary pulsatile vesicle which drives blood into the 



* ZeitscLr. wiss. Zcol., xcviii. (1911) pp. 529-625 (4 pis.). 



t Arch. Naturges., Ixxvii. (1911) pp. 39-41. 



X Jen. Zeitschr. Naturw.,xlvii. (1911) pp. 43-114 (3 pis. aud 16 figs.). 



§ Der Bau der Bieue (Stuttgart, 1911) 182 pp. (20 pis. aud 149 figs.). 



II Coruptes Eendus, clii. (1911) pp. 110-12 (1 fig.). 



