ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 431 



veloprnent outside the mother, and in the development of the lungs, 

 heart, alimentary canal, and coxal gland. It resembles that of Sol- 

 pugidae and Pseudoscorpionidse in the development of the lateral organ, 

 and that of scorpions as regards central nervous system, accessory brain, 

 median and lateral eyes, and also as to lungs, heart, coxal gland, and 

 parts of the alimentary canal and Malpighian tubes. 



Hibernating' Cyst of a Mite.* — A. 0. Oudemans describes a 

 peculiar scale-like cyst, with anterior and posterior hairs or hair-like 

 processes, which contained a fully formed Erythreeus ( = Bhyncholophus) 

 with its food-canal filled with black particles. He finds it impossible 

 to explain the process (of ecdysis and encystation ?) whereby the de- 

 scribed structure arose. 



British Tyroglyphidae.f — A. D. Michael has increased the debt 

 which zoology already owes him by adding to his monograph on British 

 Oribatidaa the first part of a companion work on Tyroglyphidse. After 

 discussing general characters, practioal importance to man, parasitism and 

 mutualism, &c, he gives a history of the literature, and a discussion of 

 the classifications proposed. Then follow two important chapters on 

 struoture and development. The rest of volume i. is systematic. The 

 whole will be an achievement to be proud of. 



Arctic Halacaridae4 — E. Trouessart makes a preliminary report on 

 the Acarina of Arctic seas, collected by the Prince of Monaco. He 

 raises the number of known Arctic species from three to nine, and four 

 of the additions are new species. Two of these Halacarus alberti and 

 H. princeps are remarkable for their large size. 



e. Crustacea. 



Regeneration in Hermit Crab and Crayfish.§ — T. H. Morgan 

 shows that regeneration of the leg of the hermit crab can take place at 

 a number of different regions lying outside of the breaking-joint, and 

 presumably, therefore, at all levels. It is thence argued that there can 

 be no connection between regeneration and liability to injury, for the 

 legs can rarely or never be broken off outside of the breaking-joint 

 under natural conditions without the leg being thrown off at the base. 



The author gives five cases showing that the crayfish has the same 

 power as the hermit crab and can regenerate the distal portions of its 

 legs when they are cut off outside of the breaking-joint. The crayfish 

 can also regenerate a new leg when the old one has been cut off inside 

 of the breaking-joint. There is no necessary connection between the 

 process of autotorny and the power of regeneration. 



Larval Stages of the Shrimp.||— H. C. Williamson confirms Ehren- 

 baum's arrangement of the larval forms of Crangon vulgaris in five 

 stages, which form a complete series all connected by observed moults. 

 He traces and very carefully figures the development of the nine pairs 

 of appendages from stage to stage. The gills, it is noted, are in all 



* Zool. Anzeig., xxv. (1902) pp. 218-9. 



t Kay Societv, 1901, xiii. and 290 pp. and 22 pis. 



X Bull. Soc. Zool., xxvii. (1902) pp. 66-70. 



§ Anat. Anzeig., xx. (1902) pp. 598-605 (17 figs.). 



|| 19th Ann. Rep. Fishery Board Scotland, 1901, pp. 92-119 (6 pis.). 



