ZOOLOGY AND BOTANY, MICKOSCOPY, ETC. 307 



cells, as Balbiaui, von Grimm, and Eitter have maintained. It is one of 

 the most striking instances of the early distinctness of germ-cells and 

 somatic cells. 



Thoracic Sensory Organs in Larval Diptera.* — D. Keillin finds 

 in all the Dipterous larvfe which he has examined a thoracic sensory 

 organ, situated on the pleura, and consisting of tliree or four sensitive 

 setge, more or less approximated at their bases. They are always situated 

 near the imaginal disks that form the limbs, and the author enquires 

 whether they may not represent a last vestige of larval limbs. This is 

 suggested, for instance, by the condition of some of the vestigial limbs 

 in certain larval Coleoptera. 



Structure of Larval May-fly.f — F. W. Leue describes the internal 

 structure of Heptagenia sulphured Miiller, with special reference to the 

 alimentary and excretory system. 



5. Arachnida. 



Histological Study of Digestion in Spiders. $ — Ernst Oetcke has 

 studied in particular the changes that go on in the epithelial cells of the 

 " liver " or mid-gut gland, his subject being the house-spider {Ti-fjenaria 

 domesticd). He also describes the minute changes in the gut itself, in 

 the connective tissue, and in the Malpighiau vessels. There is a 

 dimorphism in the epithelium of the mid-gut gland ; the larger cells 

 show clear intra-cellular digestion. But there is also extra-cellular 

 digestion, the smaller cells producing the necessary secretion. 



Studies on Mites. § — A. C. Oudemans gives a valuable account of 

 the known larvai of Thrombidiidae and Erythraeidte, with especial 

 reference to those which are injurious to man, such as the disseminator 

 of the Japanese " flood-fever," or Kedani disease. 



Mites from Caves. || — Ivar Triigardh deals with Acari collected from 

 caves in France, Spain, and Algiers. He records a considerable number 

 of Parasitidae, Oribatidfe, and TrombidiidjB, and describes some of these 

 in detail. 



f« Crustacea. 



Eyes of Deep-sea Galatheids.lf— L. von Dobkiewicz has studied the 

 varied condition of the eye in Galatheids {Munida, Mtmidopsis, etc.) 

 from different depths. Very highly specialized eyes occur in (dysphotic) 

 regions where there is little light. In a few special cases {Elasmoiiotus 

 cylindrophtJuilmus) the eyes may be completely degenerate in a dysphotic 

 region. In (aphotic) regions where no light penetrates, the eyes are 

 entirely degenerate. 



♦ 



Comptes Rendus cliii. (1911) pp. 977-9. 

 t Arch. Naturges., Ixxvii. (1911) pp. 202-31 (3 figs.). 

 X Zool. Jahrb., xxxi. (1912) pp. 245-76 (1 pi. and 2 figs.). 

 § Zool. Jahrb., 1912, Supp. 14, pp. 1-230(57 figs.). 

 il Arch. Zool. Exper., viii. (1912) pp. 519-620 (7 pis.), 

 t Zeitschr. wiss Zool., xcix. (1912) pp. 688-716 (1 pi. and 12 figs. 



