ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 559 



tion of fibrin and other albuminous bodies. Spiders do not take in 

 food in the solid form ; they dissolve the muscles, &c., of their prey, 

 and suck in the fluid food ; this passes into the final branches of the 

 enteric diverticula. 



The hind-gut commences just behind the last pair of these diver- 

 ticula. The Malpighian vessels ramify in the intermediate tissue, 

 and secrete guanin or an allied substance. This body may be found 

 deposited in the outer layer of the intermediate tissue, and it takes a 

 considerable share in the coloration and marking of the animal. 

 On the whole, it would be well, in the present state of our knowledge, 

 to substitute for the name " liver " that of " chyle-stomach." 



In the substance of the organ itself we may distinguish more or 

 less regular hemispheres of various shades, an almost completely 

 transparent tissue, and a system of fine richly branched Malpighian 

 canals ; these last have fine canals which pass into wider collecting 

 ducts, which open into a wide cloaca ; the walls of this have a distinct 

 muscular investment, formed by an outer layer of longitudinally 

 and an inner of transversely disposed fibres. 



The author gives some account of the differences which the 

 caecal diverticula present in various genera of spiders and in forms 

 allied to them. 



Anatomy of Acarina-* — J. MacLeod, in a preliminary notice, 

 states that, in his investigation of the Acarina, he has made use of 

 sections, after hardening in picrosulphuric acid or alcohol, and stain- 

 ing with carmine, but that the successful results seem to have been 

 greatly due to chance, specimens collected at the same time and 

 treated in exactly the same way behaving very differently on treat- 

 ment with hardening and staining reagents. The genera examined 

 were Trombidium, Argas, Hydrachna, and Gamasus. 



He finds that the tracheiform excretory ducts of the salivary 

 glands open separately into the labial groove at a short distance in 

 front of the buccal orifice. The description given by Henking as to 

 the presence of short narrow ducts arising from tubular glands is 

 confirmed. The suctorial apparatus of Argas differs completely from 

 that of Trombidium, accurately described by Henking ; it has three 

 branches, each of which is bifurcated, and is provided with three 

 radiating muscles. Notwithstanding the difference in their structure 

 the two organs seem to obey the same dynamical laws. 



The author has been able to definitely assure himself of the com- 

 munication between the stomach and the terminal intestine, which, 

 denied by most authors, has only been regarded by Henking as pro- 

 bable on d priori grounds. The communication is effected by a pair of 

 lateral orifices, which are extremely narrow, and have their lips almost 

 always closely applied to one another ; the difficulty of detecting them 

 is increased by the presence of a largo number of almost villiform 

 cells which are found around them. 



The terminal intestine is filled by a granular substance, which is 

 composed of brownish-yellow granulations similar to those that are 



♦ Bull. Acad. II. yci. Belg., Iviii. (1884) pp. 253-9. 



