246 Mr. A. Tulk on the Anatomy of Phalangium Opilio. 



lary action of the soft hairs upon the surface of the maxillse, to 

 flow through the trilabiate opening into the channel of the dorsal 

 plate of the pharynx; while the hard and solid parts, already much 

 softened, will be received by the larger aperture into the general 

 cavity of the latter, and undergo further trituration between its 

 lateral pairs of teeth previous to entering the oesophagus. I state 

 these opinions relative to their uses, as they have appeared to be 

 deducible from the arrangement of the parts in question, it being 

 scarcely possible, from their minuteness, to test this subject by 

 actual observation. The reader is referred to the very interest- 

 ing paper by Captain T, Hutton* upon the habits of a large spe- 

 cies of Galeodes, as affording evidence that other genera of Tra- 

 cheary Arachnida also devour their food whole. The harvest- 

 spiders, at least the present species, are nocturnal in their habits, 

 and capture their prey, consisting of flies, musquitoes, and small 

 lepidoptera, by stealing cautiously towards it, and making a gli- 

 ding spring upon the victim when within reach. Herbstf has well 

 described their predatory actions, when he says, " Sie springen 

 und stiirzen auf die Beute, wie die Katze auf die Maus, und halten 

 sie mit den Palpen wie mit Handen selbst.^' I have repeatedly 

 seen individuals of P. cornutum, when in confinement, pursue 

 each other with the utmost pertinacity, the larger generally 

 pouncing upon the smaller, and having brought them within 

 reach of the chelicerse and palpi by grappling them with their 

 long legs, proceed to devour the body, leaving the extremities 

 untouched. They use one of their legs occasionally, to sup- 

 port the food to their mouth. It may be also, that the ap- 

 pendages to the second pair of coxal joints serve some similar 

 purpose. 



I proceed now to consider the remainder of the digestive ap- 

 paratus, so remarkable from the numerous csecal pouches which 

 are given off from it, and which completely conceal the continu- 

 ation of its canal upon the upper surface. These cceca may be 

 conveniently divided, as regards their position, into those situated 

 upon the dorsal surface of the canal, those upon the ventralj and 

 others upon the sides, and, as to size, into larffe and small cseca. 

 Beginning with the superior group, the first are a pair of large 

 oblong sacs (PI. IV. fig. 17. A A), situated one upon either side 

 of the median line, and extending the entire length of the abdo- 

 men. They are somewhat broadest posteriorly, and occupy each 

 about a fourth of the width of the abdominal cavity. They are 

 attached, as arc two other pairs of long cseca, to the intestine 

 throughout their entire length, being formed, as it were, by di- 

 verticula of the coats of the latter, the edges of which, adherent, 



* Annals of Nat. Hist., August 1843. f Op. cii. 



