20 "Corona analis" in Palpatores 



genitales in Cyphophthalmi, the ridge in question in Laniatores is sharply divided off from 

 sternum by a suture. In some specimens only of Phalangodes Piochardi E. S. we have 

 noticed a slanting groove across the proximal portion of the fourth coxa, as in some Cyphoph- 

 thalmi ; but it is placed farther from the base of the coxa than in any representative of that 

 sub-order. 



We are thus enabled by a comparative study of representatives of all the families 

 comprised in the order Opiliones, to demonstrate that the apparently "five" first sternites — 

 the only ones visible in Phalangioidae — in fact represent seven sternites, of which the first, 

 the arculi genitales, embraces the genital orifice laterally and in front, whilst the second 

 carries the spiracles and bounds the genital orifice behind, operculum genitale being in reality 

 only a continuation of this stemite in a forward direction. The true third sternite is in all 

 Opiliones immovably united in the second one. 



The morphological interpretation of the posterior extremity of abdomen is attended with 

 much more diiBculty than that of the base, on account of the rather considerable difference 

 in regard to that part between the principal tj'jjes of Opiliones. In Laniatores (excepting 

 Oncopodoidffi) we find behind the true seventh sternite another large sternite (woodcut fig. K) 

 which, as we have already mentioned, evidently is made up of two. The same is the case 

 in Cyphophthalmi (PI. I., fig. 1 o) with the unimportant diffei-ence that in the latter case they 

 are small. In bc:)th these sub-orders nine sternites can thus be accounted for. Amongst 

 Palpatores a "corona analis" is found in Nemastomatoidae and Troguloidse ; but in Phalan- 

 gioidtB and Ischyropsalidoida^ only insignificant vestiges, or none at all, of .such an arrangement 

 are to be found. In Cyphophthalmi we find besides a ninth tergite situated behind, that is 

 to say, above operculum anale, but this tergite is wanting, at least apparently, in the other 

 sub-orders. It must be considered as absolutely beyond question that this ninth tergite belongs 

 to the same abdominal segment as the ventral segment which we describe as the true ninth. 



In those Palpatores where " corona analis " is well developed it consists, as is well known, 

 of four chitinized pieces, one ventral piece, placed in the middle in front of anus, a dorsal 

 piece behind anus, and a pair of lateral ones (woodcuts figs. F, G, H). There can be no 

 doubt of the dorsal piece being operculum anale, and this is acknowledged by all authors. 

 As regards the lateral pieces, the following views have been propounded : in 1876 Thorell 

 {a, p. 458) says "The ventral [median] and the two lateral ones together seem to represent 

 the two last typical [ventral] segments, the eighth and the ninth." Simon (6, p. 119) 

 considers that they belong to one and the same sternite, which he considers to be the last, 

 viz. his sixth ; finally Hansen (a, p. 494) has advanced the view, that the lateral pieces and 

 operculum anale belong to each other. We cannot adopt any of these views. That the median 

 ventral piece belongs to the ventral surface of the body cannot be doubted : but that is not 

 the case with the lateral pieces. A careful examination of certain forms such as Nemastoma 

 and Anelasmocephaliis (woodcuts figs. R and G) reveals that the posterior part of the median 

 piece — which is not visible unless the operculum anale is lifted up — is separated from the 

 anterior portion by a transverse gi-oove, which indicates that the piece in question is formed 

 by the union of two sternites. The posterior of these sternites is, even when comparatively 

 large, very small, and fused with the preceding one, and in some forms it is not traceable. 

 The lateral pieces of " corona analis " extend upwards between operculum anale and the 

 eighth tergite. If now we compare the anal region of a Nemastoma or a Troguloid form 

 (woodcuts H and G) with that of some rej^resentative of the sub-order Cyphophthalmi, for 



