372 SUMMARY OF CUERENT RESEARCHES RELATING TO 



are localized in the branchial sac, and the blue in the regions of the 

 viscera, etc. Some of the unpigmented cells are amoeboid : others are 

 not. In the green cells the pigment is a compound containing vanadium, 

 probably in a stage of oxidation corresponding to V2O3. It is not a 

 respiratory pigment, but is most likely of value as a catalytic agent. 

 The coagulation of the blood depends on the agglutination of its cells. 

 Clotting often occurs within the intact blood system as a result of 

 vigorous external stimulation. 



The heart is long and has a node (demonstrable physiologically and 

 anatomically) which divides it unequally. A pericardial body is present. 

 In most specimens a pulsation series shows about twice as many advisceral 

 beats as abvisceral beats. The pulse-rate decreases as the size of the 

 animal increases. It is greater in the advisceral phase, and the velocity 

 of the contraction-wave is greater in the advisceral direction. There is 

 a circulation of the blood in the advisceral direction. The reversal of 

 the heart-beat may be due to the alternating dominance as pacemakers 

 of the two ends of the heart. The heart-beat is myogenic, and the 

 contraction wave passes along the muscular elements across the heart. 



J. A. T. 



INVERTEBRATA. 



MoUusca. 

 a. Cephalopoda. 



Posterior Salivary Glands of Cephalopods. — F. Botazzi {Atti R. 

 Accad. Lincei Rend., 1918, 27, 191-6, 227-30). Experiments on the 

 toxic action of the secretion of the posterior salivary glands of Octopus 

 macropus point to the effect being due to the presence of substances 

 analogous to tiramine, histamine, and coline in the secretion. The 

 rapid effect of the secretion on the crabs which the cuttlefish bites 

 is well known. The secretion also digests crab-muscle, and contains 

 proteolytic and peptolytic ferments. J. A. T. 



Arthropoda. 

 a. Insecta. 



Reflex Immobilization in Arthropods. — E. Eabaud {Bull. Soc. 

 Zool. France, 1918, 42, 140-5). Some insects become "immobile" 

 when turned back downwards, and may remain stiff for a few seconds 

 or for as long as twenty minutes. This is well seen in several dragon- 

 flies (e.g. Lestes viridis and Aeschna cyanea). The immobility lasted 

 for about thirty seconds in Gordulogaster annulatus, for twenty minutes 

 in Calopteryx splendens. The phenomenon was also observed in some 

 Lepidoptera (e.g.Spilosoma menthastri), some Diptera (e.g. Dexia rustica), 

 and very markedly in an Asilid, Machimus pilipes. The removal of 

 the tarsal joints from all contact with a surface is the immediate factor 

 which puts a stop to mobilizing stimuli and allows immobilizing influences 

 to get the upper hand. In active flight the tarsal excitation is replaced 

 by that of the wing-beats and by visual stimuli. J. A. T. 



