ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 171 



E. Ray Lankester, and heads with the appropriate quotation from Gaudry 

 " Vienx habitants de la terre, apprenez-nous d'ou vous etes venus." 



After an historical introduction, the author gives a general account of 

 the structure, development, and habits of the Onychophora. 



He recognises two families : (1) Peripatidae R. Evans, including 

 Per ipatus Pocock, Eoperipatus R. Evans : (2) Peripatopsidse n. f., 

 including Peripatoides Pocock, Ooper ipatus Bendy, Opisthopatus Purcell, 

 Par aper ipatus Willey, and Peripatopsis Pocock. Then follows the 

 systematic description of species, which takes account, so far, of 1 9 species 

 of Per ipatus. 



Arthropoda. 



a. Insecta. 



Ocelli of Ephemerids.* — W. Seiler finds that the ocelli of Ephemeridae 

 are epithelial, anaxonial structures, surrounded by a pigment cup com- 

 posed of a single layer of epithelium, with a lens composed of distinct 

 cells, and of hypodermal origin. Two types are distinguished which 

 differ in the structure of the lens and in the behaviour of the cornea- 

 forming cells. 



Germ-Cells of Aphides.f — N. M. Stevens finds in Aphis rosce and 

 A. Oenothera that the ova have five pairs of chromosomes, which exhibit 

 no reduction in the parthenogenetic eggs. In all cases only one polar 

 body is liberated, and it has no role in development. In the resting 

 eggs and in the spermatogenesis there is a reducing process. The 

 chromosomes conjugate in pairs and are then divided by two longitudinal 

 divisions. There is no accessory chromosome, so McClung's theory of 

 sex-determination is rejected. The author believes that the determina- 

 tion is due to external influences operating on the egg. 



Heart of Mallophaga.J — E. Fulmek has studied Lipeurus baculus, 

 Goniocotes compar, Trichodectes subrostratus, Gyropus gracilis, and a 

 species of Nirmus, with especial reference to the heart. He concludes 

 that the dorsal blood-vessel of Mallophaga has only a few pairs of ostia 

 (2-3), which are restricted to the hindmost region — the heart, in the 

 strict sense. The heart lies in the 7th abdominal segment, or on the 

 boundary of the 7th and 8th segments. It is continued forwards in an 

 aorta which is independently contractile in its posterior portion. 



Malpighian Tubules. § — A. Veneziani describes the minute structure 

 of the Malpighian tubules in a large series of insects, discussing also their 

 colouring matter, contents, number, polymorphism, and precise mode of 

 excretion. There is a constant relation between the surface area of tho 

 tubes and the mass of the body ; the number is not indefinite, but 

 reducible to three groups of 2, 4, and 6, which may be simple or much 

 branched ; the pigment is a urochrome (entomurochrome) : the sub- 

 stances excreted are uric acid, urates, phosphates, oxalate of lime, to 

 which may be added carbonate of lime or soda, leucin (in Dytiscidse), 



* Zool. Jahrh., xxii. (1905) pp. 1-40 (2 pis. and 1 fig.). 



t Joum. Exper. Zool., ii. (1905) pp. 313-33 (4 pis.). See also Zool. Zentralbl., 

 xii. (1905) pp. 809-10. % Zool. Anzeig., xxix. (1905) pp. 619-21 (1 fig.). 



§ Redia, ii. (1905) pp. 177-230 (3 pis). 



