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Annals of the Transvaal Museum 
extending ventralwards on each side, is not very extensive, but in 
Chelypus and Hexisopus the lateral extensions are quite strongly de- 
veloped, and the head-region is thus particularly robust. Normally, the 
lower portion of this lateral extension is separated from the upper only 
by a deep broad groove, but in Blossia the compound nature of the 
structure is indicated by a well-marked suture line, running immediately 
ventral to the somewhat ill-defined groove and separating off the lowest 
portion of the lateral extension as a distinct sclerite: the suture line is 
faintly indicated also in other genera. This sclerite may possibly be an 
isolated anterior portion of the first tergite, but in Blossia is not com- 
pletely fused with the forward continuation of what appears to be the 
first thoracic tergite. It may also be noticed that whereas in most 
Solifugae the anterior lateral lobe of the head-plate, which is said to 
bear rudimentary eyes 1 , is only partially separated from the main 
plate, a more complete separation occurs in Chelypus, where a fairly 
distinct suture line extends backwards to the posterior margin of the 
plate. 
The segmentation of the legs, excluding the tarsi, is fundamentally 
similar throughout the order. Dr Purcell in describing Hexisopus (9) 
laid some stress on the supposed fact that this genus has a reduced 
number of trochanter segments, thus differing from all other known 
genera. The same view seems to have been held previously by Mr Simon, 
for, in his account of Hexisopus fodiens, the trochanter segments are 
given as two, and the tarsal segments also as two. In Das Tierreich, 
Purcell’s views on the homology of these leg segments are mentioned, 
but Kraepelin adopts what is undoubtedly a more correct interpretation, 
without however presenting any reasons for his homologies. In most 
Solpugids, the distal trochanter segment of legs II-IV is very character- 
istic, having a dorsal infolding of chitin marked externally by a definite 
line extending over the length of the segment. In Hexisopus, this line 
is scarcely noticeable, and as the third trochanter of leg IV is greatty 
elongated, like a femur, whilst the true femur is abbreviated, a confusion 
of homology is not surprising. The third trochanter of leg IV in Chelypus, 
however, shews the dorsal line very distinctly and there can be no doubt 
of the identity of the segment. The homologies of the leg segments can 
also be traced quite independently from the character of the articula- 
tions, certain of which are quite distinctive. In a Solpuga, there are 
specialised areas of thickened chitin arranged in pairs at particular 
joints, where the movements of the segments concerned are restricted 
to one plane, viz. between the patella and tibia of the palp, between the 
femur and patella, and between the patella and tibia of all the legs. In 
the second or third leg of Chelypus these can be seen without difficulty, 
and, relying on this character alone, the third leg of Chelypus is found 
to have three fairly large trochanter segments but only one tarsal 
segment. 
In the terminology of the segments of the legs, I prefer to follow 
1 W. Sorensen was unable to find the rudimentary eyes, nor could the present writer. 
In the recent edition of the Encyclopaedia Bvitannica, E. R. Lankester speaks of “a 
pair of median eyes and obsolete lateral eyes on each side.” 
