ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 435 



gills. GrijUus has, although a degenerate form, a primitive organisation 

 which serves as a link connecting most insect orders. 



Species of Poeciloptera.*— A. Jacobi discusses this genus, and in 

 particular the series of forms which may be ranked under P. phakcnokles, 

 with the aim of showing that the facts support the theory of the origin 

 of species by spatial isolation. He indicates that this view is gradually 

 supplanting the theory of the origin of species by natural selection. 



5. Arachnida. 



Ticks as Transmitters of Bovine Diseases.f — A. Laveran and M. 

 Vallee report that they received from M. Theiler, a veterinarian at Pre- 

 toria, some larvae of the tick Rhipicephdlus decoloratun, which he had 

 found to be the transmitter of spirillosis in cattle. The mother-tick 

 had been taken from an infected beast. Messrs. Laveran and Vallee 

 have verified the experiment ; the ticks were put on healthy beasts, and 

 spirillosis soon resulted. Piroplasmosis also ensued. 



Fertilisation in Mites.J — E. Trouessart describes the mode of 

 insemination in Sarcoptidas and Tyroglyphidse. The sperm is stored 

 in a special receptaculum seminis ; the coitus occurs through a special 

 opening in the female, remote from the genital opening, which serves 

 only for the liberation of eggs or embryos. Usually the male unites 

 not with an adult female but with a sexually mature nymph. The ex- 

 ternal sperm-sac opening in the nubile nymphs of Sarcoptidie and 

 Tyroglyphidaj appears after and in consequence of copulation. The 

 male must pierce the opening with his pointed chitinous penis. 



Arachnological Notes. § — VI. Kulczynski describes some new species, 

 e.g. Rhomphma longa, Lephthyphantes Jcotulai, Saitis grcvca, and makes a 

 note on the stridulatory organs in both sexes of many Theridiidas. 



New Breathing Organ in Mites. || — K. Thon describes in the genus 

 Holothijrus Gerv. a new respiratory structure. Behind the stigma slits 

 there is a roomy vestibulum, which through a narrow passage leads to a 

 larger atrium. Both chambers are covered with epidermis, and from 

 the atrium there arise a number of tracheal branches. The atrium 

 appears to be connected by muscle strands to the dorsal wall of the 

 body. There are other peculiarites reserved for future consideration, in 

 view of which the author removes the genus from the order Mesostig- 

 mata, establishing a new order, Holothyrida, for its reception. 



<• Crustacea. 



Notes on Crustacea. *[ — H. Coutiere gives some notes on certain 

 oceanic Macrura obtained on a cruise of the 'Princess Alice' by 



* SB. Ges. Natur. Freunde, Berlin, 1904 pp. 1-14 (2 figs.), 

 t Comptes Rendus, cxl. (1905) pp. 1515-17. 



X Comptes Rendus Soc. Biol., lvi. (1904) pp. 367-8. See also Zool. Zentralbl.. 

 xii. (1905) pp. 32-3. 



§ Bull. Internat. Acad. Sci. Cracovie, (1904) pp. 533-G8 (1 pi.). 

 U Zool. Anzeig., xxviii. (1905) pp. 585-94. 

 f Comptes Rendus, cxl. (1905) pp. 1113-15. 



2 G 2 



