ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 379 



hatching (on the leg) lasted seven to eight days ; there are three moults 

 and larval stages before maturity is reached ; the life-cycle is completed 

 in twenty-two to twenty-seven days (on the leg). The feeding is prac- 

 tically .continuous, interrupted only by moulting, and the insects die 

 very quickly when removed from the host. Warmth attracts them when 

 they are removed from man. (See also p. 304.) J. A. T. 



S. Arachnida. 



Notes on Mussel-mite. —Ernest Carroll Favst (Trans. Amer. 

 Micr. Soc, 1918, 37, 125-X, 1 pL). There is a wide range of variability 

 in the species Unioiiicola aculeata, and some of the peculiarities of the 

 material dealt with are recorded. Special attention is directed to the 

 heteromorphic fourth leg of the male. The external male genital organs 

 are very complicated, consisting of an ornate sculpture of chitin, to 

 which prominent muscle-bands are attached. As Koenike has shown, 

 the mite is free-swimming during a considerable part of its life, and 

 seeks the mussel at times of metamorphosis and propagation. Those 

 dealt with in this paper were embedded in thin cysts in the subdermal 

 connective-tissue of the mantle and foot, and had done no harm outside 

 the cyst. J. A. T. 



Mange Mites. — E. L. Trouessart {Bull. Soc. Zool. France, 1918, 

 42, 151-8, 3 ligs.). The pilicolous Sarcoptids of mammals form a series 

 parallel to that of the plumicolous Sarcoptids of birds. In the latter, 

 however, the most marked peculiarities are seen in the adaptations the 

 males show for catching and holding the females ; in the former the 

 most marked peculiarities are adaptations for gripping the hair, and may 

 be seen i]i both sexes. Some of the varying fixing organs are figured 

 and described. The author establishes two new genera, Euryzonus 

 (depressed and elongated), and Atopomelus (compressed laterally). 



J. A. T. 



Intracellular Dig-estion in an Acarid. — Ed. Reichenow {BoU. 

 R. Soc. Espan. Hist. Nat., 1918, 18, 258-73, 4 figs.). In a Gamasid, 

 Llpomjssus saurarimi Oudemans, which is a carrier of the blood 

 parasites of the wall-lizard, there is in the mid-gut a process of intra- 

 cellular digestion. In the cells of the lining epithelium there are to be 

 seen red blood corpuscles of the host in process of digestion. It appears 

 that there is little or no secretion of digestive juice into the lumen of 

 the gut, though bacterial action may have a liquefying effect. The 

 epithelial cells act as phagocytes, and exhibit intracellular digestion, as 

 in lower Metazoa. Oocytes occur among the epithelial cells of the 

 intestinal wall and take a direct part in the absorption. The author is 

 inclined to think that the limits of the occurrence of intracellular 

 digestion are much wider than has been supposed. J. A. T. 



Mites as Disease-carriers.— G. Tegdora {'' Redia,'' 1918, 13, 

 105-14.). This paper discusses in particular the species of mite, 

 apparently Leptus aJcamushi, which is the vehicle of a Japanese river- 

 fever. Attention is also directed to Dermacentor venustus, which 



