212 ARACHNIDES. 



FAMILY III. 



HOLETRA(l). 



The trunk and abdomen are here united in one mass, urtder 

 a common epidermis, or at most, the thorax is divided by a 

 strangulation, and the abdomen, in some, merely exhibits an 

 appearance of annuli, formed by the plicai of the abdomen. 



The anterior extremity of tlieir body frequently projects 

 in tile form of a snout or rostrum ; most of them have eight 

 legs, and the remainder six(2). 



This family consists of two tribes. In the first or the Pha- 

 LANGii A, Lat., we observe very apparent chelicenu which 

 either project in front of the trunk, or are inferior, and always 

 terminating in a didactyle forceps, preceded by one or two 

 joints. 



They have two filiform palpi, composed of five joints, the 

 last of which is terminated by a small nail ; two distinct eyes; 

 two jaws formed by the prolongation of the radical joint of 

 the palpi, and frequently four morc(3), wliich are also a mere 

 dilatation of the liip of the two first pairs of legs. The body 

 is oval or rounded, and covered, the trunk at least, with a 

 firmer skin ; there is also an appearance of annuli or plicae on 

 the abdomen. The legs, of which there are always eight, are 

 long, and distinctly divided, like those of Insects(4). At the 



(1) HoLETRA, Hermann. 



(2) The Tromhidium longipes, Hermann, Jun., Mem. Apter., pi. I, 8, is repre- 

 sented with ten legs, the two first very long. He allows but eight in the text. 



(3) If we suppose that the two superior jaws, with their palpi, represent the 

 mandibles of the Crustacea Decapoda, the other four will also represent the jaws 

 of the same animals, and the two jaws and inferior lip of the triturating [Broyeurs') 

 Insects. From M. Marcel de Serres we learn that the ganglion which immediately 

 follows the brain, is opposite to the third pair of legs, which, according to these 

 approximations, are analogous to the first pair in Insects; now, there also we find 

 the same ganglion in the latter. See Myriapoda. 



(4) The hips, thighs, tibix, and tarsi are the same as in the preceding families. 

 But the legs of the Arachnides Tr.acheariae are composed of short joints, whose rela- 



