308 ME. H. M. BERNAED ON THE 



great Avork on the Arachnids in ' L'Organisation clu Regne animal ' contains heantiful 

 drawings of the anatomy of Galeodes, but vmfortnnately, beyond the explanation of the 

 plates, the text is wanting. The most exhaustive account of the Galeodidae is from the 

 pen of the illustrious French naturalist Dufour. His " Anatomie, Physiologic, et 

 Histoire naturelle des Galeodes " (31) has the special advantage that the author's 

 previous studies on Scorpio enabled him to handle the subject comparatively. In 

 addition to these three works, there have been several small articles dealing with special 

 points. Systematic papers have naturally not been taken into account, the object of 

 this paper being purely anatomical and morphological. 



I. The External Form and Segmentation*. 



Fusion of Segments. — The general form of the Galeodidae (PI. XXVII. figs. 1, 11, 15 ; 

 PI. XXIX. figs. 3, 4, 6) is so well known that we need discuss only the points of mor- 

 phological interest. 



The Galeodidae show the primitive metamerism of the body more markedly than any 

 other Arachnid, the first three segments of the cephalothorax being the only fused 

 segments in the body. The three posterior segments remain movable. The abdominal 

 region consists of ten segments, all of which are free. This limitation of the fusion of 

 ■segments to the first three is a very important point in endeavouring to fix the systematic 

 position of the family. 



In the Scorpionidse, Thelyphonidse, and Psoudoscorpionidse, while the segments of the 

 abdominal regions are free, the segments of the cephalothorax have been fused together. 

 In the Araneidse, all the segments both of the cephalothorax and of the abdomen are 

 fused into two groups, the first six forming the cephalothorax and the last ten forming 

 the abdomen. Scldzonotus is the only other Arachnid which, like Galeodes, has retained 

 free cephalothoracic segments, but it is not easy to make out the segmentation 'exactly. 

 There are certainly two free segments, and I should not be surprised if there ultimately 

 prove, on examination of favourable specimens, to be three, as in Galeodes. 



Segmentation of the Dorsal Surface : Cephalothorax. — Behind the large plates of 

 the cephalic lobes {cl.), we can trace three clear segments, /. e. the 4th, 5th, and Gth, and 

 the remains of the 3rd not quite obliterated by the cephalic lobes. The details can 

 be gathered from figs. 1-7 (PI. XXVII.). 



The terga of segments 5 and 6 have remained practically unmodified, and are the 

 direct forward continuation of the series of abdominal terga (fig. 1). The tergum of 

 segment 4 has undergone a striking change. The Galeodidae can bend the body not 

 only between the Gth and 7th segments (at the waist), but also between the 4th and 

 5th. To facilitate this anterior bending, the greater part of the tergum of the 4th 

 segment is soft and flexible, while what I assume to be its anterior edge has given rise 

 to two spring-like rods, the tips of which fuse anteriorly with the posterior border of a rim 



* Since, in the Arachnida, the limbs are typically arranged as foUows : — two pairs grouped round the mouth, viz., 

 the chelicera3 and the pedipalps, and four pairs as ambulatory legs — it is a matter of indifference whether we speak 

 of them as chelicerie, pedipalps, and Ist, 2nd, 3rd, and -Ith pairs of legs, or as appendages 1-6. In what follows, both 

 designations are used, the 1st leg meaning the 3rd appendage, and so on. 



