Miscellaneous, 273 



the dif^stion of the ^\jachnidans. The very special organization of 

 the rhalangida permitted this separation. 



It is not ray intention to summarize here the anatomical part of 

 my note ; but I must say a few words on the arrangement of the 

 digestive tube of the ^Vraneida and of the Phalangida in order to 

 show the bearing of the physiological results. 



The Araneida, or spiders properly so called, are sucking animals. 

 Their digestive tube comprises : — first, a buccal intestine entirely 

 situated in the oephalothorax, and consisting of an oesophagus with 

 chitinous walls, terminating with an apparatus of suction, accom- 

 panied by a series of five pairs of lateral cajca ; then, in the abdo- 

 men, a middle intestine, followed by a terminal intestine. The 

 middle intestine is here characterized by the fact that it receives 

 on the right and left the excretor}' canals from the voluminous 

 abdominal gland, hitherto called the liver in the Araneida. The 

 terminal intestine, dilated into a reservoir, receives at its origin, as 

 in all the Articulata, the crustaceans excepted, the Malpighian or 

 urinary tubes. 



AVe know by the works of Ramdohr, Treviranus, Tulk,'Blanchard, 

 &c., that the digestive apparatus of the Phalangida is quite different. 

 Here the animal docs not suck its prey, but devours it entirely. 

 The digestive tube consists, in the first place, of a buccal intestine 

 reduced to a short oesophagus ; then of an immense median sac, 

 into which open dorsally about thirty voluminous caeca filling 

 nearly all the ca\'ity of the body ; lastly of a short terminal intes- 

 tine, characterized, as I show for the first time, by the insertion of 

 the Malpighian tubes. It is to be remarked that here the body is 

 no longer distinctly divided into a cephalothorax and an abdomen, 

 and also that, as in the ^\janeida, a certain number of caeca penetrate 

 into the coxopodites of the feet. 



AH authors taking for their basis a simple resemblance of form, 

 regard the caeca of the Phalangida as the analogues of the cephalo- 

 thoracic cax;a of the Araneida. This is for want of histological 

 observations and above all of physiological experiments. 



Experimental researches already far advanced have convinced me 

 that the volumijious gland called the liver in the Decapod crustaceans, 

 and which empties its products into the middle intestine of those 

 animals, is nothing but the organ of secretion of the digestive licjuid 

 intended for the emulsion of the fats and for the solution of the 

 albuminoids *. Recently M. Jousset de Bellesme has informed me 

 that he has arrived at perfectly similar results ; finally a number of 

 experiments on the so-called liver of the Araneida t, the ducts of 

 which also open into the middle intestine, have proved to me that 



• I have already alluded to it in my * Recherches sur les ph^nomenes 

 de la digestion, etc. . . des Myriapodes,' p. 42, note 4. 



t i take this opportunity of calling the attention of the reader to tb« 

 importance of the results of my experiments on the Araneida. The 

 memoir in which they, together with numerous ctlier facts, are to b« 

 found, and which I hope to complete shortly, will, I hope, be read with 

 interest. 



Ann. & Mag. N. Hist. Ser. 4. Vol xix. 19 



