PHALANGIOTARBIBvE. 45 



Order PHALANGIOTARBI, Haase. 



1890. Opiliones, sub-order Phalangiotarbi, E. Haase, Zeitsclir. deutscli. geol. Ges., vol. xlii, p. 650. 

 1910. Phalangiotarbi, E. I. Pocock, Geol. Mag. [5], vol. vii, pp. 508—512. 



Carapace of prosoma unsegmented, bearing a single pair of median eyes near 

 its anterior border. No constriction between the prosoma and opisthosoma, but the 

 two regions apparently movably jointed together. Terga of the opisthosoma eight 

 or nine in number and referable to two categories ; the anterior five or six 

 quite short and apparently movably jointed, the posterior three long and 

 apparently fused, though the sutures between them persist. Sterna of the 

 opisthosoma apparently only seven in number, the posterior three corresponding 

 with the posterior three terga and the anterior four with the anterior six terga ; 

 the first sternal plate triangular and wedged between the coxa? of the last pair of 

 appendages of the prosoma. The genital orifice either just in front of or just behind 

 this plate. The anal orifice small, subapical, and perhaps closed by an operculum 

 representing a tenth segment. Legs, where known, alike in structure and con- 

 sisting of seven segments, of which the fourth or patella is subequal in length to 

 the third (femur) or fifth (tibia). Palpi, where known, very short, slender, and 

 pediform. 



This Order is wholly extinct and is only known from the Coal Measures of 

 Europe and North America. 



Although this group has some structural points in common with the recent 

 Opiliones, such as the single pair of eyes, the absence of constriction between the 

 prosoma and the opisthosoma, the presence of probably ten segments in the 

 opisthosoma and the simple, not chelate, palpi, I think it advisable, in the present 

 state of our knowledge, to keep the two apart, the segmentation of the opisthosoma 

 in the Phalangiotarbi being quite unlike that of the Opiliones. 



Fam ill) PHALANGIOTAEBIDiE. 

 Phalangiotarbidm, Haase and Pocouk (references as above under Phalangiotarbi). 



Sternal area of prosoma relatively large and longitudinally elliptical, consider- 

 ably longer than wide. The coxa; of all the post-oral appendages radiating round 

 it, with their distal margins overlapped by the edge of the carapace. Coxae of the 

 palpi narrow, and in contact in the middle line in front ; coxa? of legs of first pan- 

 lying on each side of them and diverging obliquely forwards and outwards, not m 

 contact with each other; those of the fourth pair diverging obliquely backwards 

 and widely separated at their proximal ends and followed by a pair of coxa-like 



