1897.] Mfi. E. 1. POCOCK ON ethiowan spidees. 725 



species so frequently spoken oB in a comprehensive sense as 

 '■ My gale.' These belong to the suborder to which I have else- 

 where applied the name Mygalomorplice, and differ from the vast 

 majority of other spiders in possessing two pairs of lung-sacs, 

 instead of one pair of lung-sacs and a pair of tracheal tubes, and 

 in the circumstance that the mandibles project horizontally for- 

 wards, instead of vertically downwards, and that the fang closes 

 almost longitudinally, instead of obliquely, backwards. The African 

 species presenting these features appear to me to be conveniently 

 referable to four families, each containing a considerable number of 

 genera and each in its broad outlines easily distinguishable from 

 the rest ; though, as is the case in almost all the groups of this 

 rank within the order Aranese (Spiders), not to mention other 

 divisions of the Animal Kingdom, genera occur in each family 

 which more or less partake of the characters of one or more of the 

 others and makes the task of drawing a hard-and-fast line between 

 the groups a task of no little difficulty. This consideration has 

 induced Mons. Simon, and following him Dr. Thorell, to look 

 upon all the genera mentioned in this paper, as well as many others 

 from different geographical areas, as belonging to a single family. 

 But it appears to me that the sections here recognized as families 

 and subfamilies have a greater value, and are more easily defined 

 than M. Simon's families Theridiidce and Argiojndce, and all the 

 subfamilies of the latter, the diagnostic features of which he has not 

 attempted to express in tabular form. 



The families may be recognized as follows : — 



a. Tarsi with only two claws on the legs, but furnished on 



each side of them with a dense tuft of hairs (ungual 

 tufts). 

 a'. The terminal segment of the posterior spinning-organs 

 long; mandible without any apical setiform spines 



forming a 'rastelhim' Theraphosid.B. 



b'. The terminal segment of the posterior spinning-organs 

 short and obtuse ; mandible usually with a set of stout 

 spiniform setae forming a ' rastellum' BaryCueliu e. 



b. Tarsi with three claws and almost always no ungual tufts. 



a^. Posterior spinners long and slender like those of the 

 Theraphosidse, but longer ; the anterior spinners 

 more widely separated ; lower edge of mandible 

 with a single internal row of teeth, as in the Thera- 

 phosidse and Barychelidre; no rastellum on mandible. Diplurid^. 

 b^. Posterior spinners shorter and thick, the anterior 

 adjacent : mandible armed below with two rows of 

 teeth. 

 c^. Mandible long, projecting as in the preceding 

 families, with the fangs closing almost straight 

 backwards ; furnished with a rastellum either in 

 the form of setiform spines or of a spine-tipped 

 process ; thoracicfovea usually strongly procurved. 



(Ground Trap-door Spiders.) Ctbnizid^. 



6'. Mandibles short, curving abruptly downwards ; 

 the fangs short, stout, and closing more obliquely 

 inwards ; not armed with a rastellum ; thoracic 

 fovea strongly recurved. (Tree Trap-door 

 Spiders.) Migid^. 



