ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 947 



processes in these cells at that time. This intensity may be explained, 

 to some extent, by the slowness of the circulation during and immediately 

 after the moulting. As only two forms are constant, it must obviously 

 be those two which, from this point of view, are of most importance. 

 The difference of reaction between the amoeboid and the coloured cells, 

 and the af&nity between the amoeboid cells and the leucocytes of higher 

 animals, enable us to determine the role of these elements, up to a certain 

 point, with much probability, if not certainty. 



e. Crustacea. 



Castration of the Cray-fish.* — M. G. Stamati remarks that no one 

 has yet attempted to castrate any animals except Mammals and Birds. 

 He failed when he tried to inject by the male deferent diicts an aqueous 

 solution of acetic acid, or to directly extirpate the gonad and duct ; the 

 best way is to remove the deferent duct by an incision in the membrane 

 which separates the cephalothorax from the abdomen, by the insertion of 

 very fine forceps. The animal must then be put into a very small 

 amount of water, sufficient for breathing purposes, but not sufficient to 

 enter the wound, which, after a time, heals. He promises to communi- 

 cate what the results of this experiment are, but time is necessary for the 

 observation of them. 



Digestion in Cray-fishes.f — M. G. Stamati has made some observa- 

 tions on digestion in cray-fishes by the aid of gastric fistulte. The fluid 

 of the stomach produces almost instantaneously a permanent emulsion 

 and saponification of a neutral oil ; it converts cane-sugar into inverted 

 sugar, changes uncooked starch into glucose, and forms peptones from 

 proteid foods. The gastric juice, which is secreted continuously, was 

 found to be formed by the so-called liver, which is a gland of double 

 function, for, in addition to giving rise to the changes just enumerated, 

 the gland contains glycogen, the quantity present of which varies with 

 the food. Lecithin and cholesterin can be obtained from this gland. 

 There is a colouring matter in the organ, but it cannot be said to be 

 analogous to the biliary secretions of Mammals. Like some preceding 

 writers, M. Stamati proposes to call this organ of double function a 

 hepatopancreas. 



Innervation of Crabs' Claws.J — Prof. W. Biedermann, in his 

 twenty-first communication on the physiology of nerve and muscle, 

 reports the results of his investigation of the innervation of crabs' claws. 

 In the first place he discusses the changes in form observed in the two 

 antagonistic muscles under the influence of electrical stimulation of the 

 nerves supplying the claws. In the second place, he describes the 

 electromotor activities in the closing muscles on tetanic stimulation of 

 the associated nerves. "All the observed consequences of indirect 

 stimulation of the claw muscles of the crab seem to find their simplest 

 explanation in the supposition that each of the two muscles is provided 

 with two functionally distinct, inhibiting and stimulating nerves." 

 " These nerves, which, on the theory maintained by Lowit and Gaskell, 

 may be described as ' Assimilirungs- and Dissimilirungsnerven,' induce 

 by their excitation opposite conditions in the muscle substance, which 



* Bull. Soc. Zool. France, xiii. (1888) pp. 188-9. f Ibid pp 146-51 



J SB. K. Akad. Wiss. Wien, xcvii. (1888) pp. 49-82 (4 pis.). 



