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Mr. R. I. Pocock on Liphistius and its 



XXXVIII. — Liphistius and its hearing upon the Classification 

 of Spiders. By R. I. PoGOCK. 



The characters of the rare genus Lijjhistius, which is known 

 only from a few specimens, one of which is preserved in the 

 British Museum, have been more or less completely set forth 

 in the writings of Schiodte, Cambridge, and Van Hasselt. 

 From time to time, moreover, Dr. Thorell has given us his 

 views on the affinities of the genus and the importance of 

 its peculiarities, his final decision being that it should consti- 

 tute a distinct tribe of the Tetrapneumones, equal in value to 

 the Territelarige, the latter group being the tribe to which he 

 had previously referred it. This classification places Liphis- 

 tius on a higher pedestal than it has occupied before ; but, as 

 a result of an examination of the Museum example, the con- 

 viction has forced itself upon me that even now the signifi- 

 cance of its structural features has been immensely under- 

 rated and the homologies of some of its characters not properly 

 understood. No excuse therefore need be sought for briefly 

 recapitulating the most important points of its organization. 



Fig'. 2. 



Fig. 1. — Liphislws desultor. Lower surface of abdomen, to sliow the 

 eight spiiiniiig-maiumilla) and the two steruites. 



Fig. 2. — Filistata, sp. Spinniug-mammillae, showing the form and posi- 

 tion of the crihellum. 



There are two pairs of spinning-mammillaj, an anterior and 

 a posterior, situated near the middle of the lower surface of 

 the abdomen, immediately behind the posterior pair of lung- 

 sacs. The anterior mammillge are considerably larger than 

 the posterior, but otherwise scarcely differ from them in 

 structure. Each may be described as consisting of two 

 segments, the distal of which is itself composed of a series of 

 annular sclerites. Between these principal mammill£e there are 



