Position of Odoriferous Glands 45 



the first coxa, is bent inwards, and on this part an oval, raised, firmly cliitinized ring 

 is seen surrounding a somewhat depressed area, where the skin is thinner, and in which 

 a short fissure appears. When one has become familiar with the appearance of this region 

 the prominent external part of the oval ring may be recognized above the coxa without 

 dismembering the animal. In Trogulus rostratus we have found a somewhat similar structure ; 

 but onl\' the external half of the oval ring is here developed, and it is thinner and less 

 firmly chitinized ; it is placed on the lower face of a somewhat convex part above the first 

 coxa and is visible only when the free distal part of coxa is bent strongly downwards, 

 because the erect slender spines on coxa standing in a close row form a complete screen 

 round the lateral depression between the lateral border of cephalothorax and the basal 

 portion of the free upper surface of coxa. According to Sorensen {h, p. 184 note) the 

 small elongated gland is found in the thicker portion of the lateral part of cephalothorax. 

 On the strength of these facts it may be considered a character common to the whole 

 order that a pair of odoriferous gland.s, stink glands, are found in cephalothorax. 



There is, however, one more point in connection with the odoriferous glands which 

 deserves consideration, viz. the position of their openings, which is of interest on account 

 of its systematic value within the order. In all Palpatores the orifices of these glands, as 

 well as the glands themselves, are placed above the end of the first pair of coxte. In 

 Ischyropsalidoida;, Leiobunum, Gagrella, and those other genera where the openings are smaller 

 than the width of the coxa they are plainly enough placed above the posterior part of 

 coxa. In all Laniatores the openings are situated above the anterior half of the terminal 

 part of the second pair of coxae. In all Cyphophthalmi, finally, they are placed above the 

 space intervening between the terminal parts of the second and third pairs of coxaj. These 

 positions are constant whatever be the .shape of cephalothorax and whether coni foetidi 

 are placed nearer to or farther from the lateral border of cephalothorax. In Stylocelhts, 

 the only representative of Cyphophthalmi endowed with eyes, these are placed closely, or 

 at a short distance, in front of coni foetidi, but in Ischyropsalidoidaj and, particularly, in 

 Phalaugioidae, the protuberance on which both eyes are placed stands at a considerable 

 distance, obliquely behind the openings of the odoriferous glands. This difference in the 

 relative positions of these two sets of organs, is certainly wary great, but it will be seen 

 on examination that they both belong to that part of the body which must be looked 

 upon as constituting the head in Arachnida, that is to say, that part of the body which 

 is formed by those segments to which the eyes and the first four pairs of appendages 

 belong. Unfortunately no trace is visible in Cyphophthalmi of a boundary between the 

 segments to which the second and third pairs of legs belong, but, as we have already 

 pointed out, coni foetidi are placed opposite the interspace between the second and third 

 pairs of coxae, that is, as far back as would be possible at the lateral border. We would 

 therefore observe that, in spite of the difference as regards the position of the odoriferous 

 glands, which w-e have just described, and which certainly is, at least apparently, very 

 considerable, there is no room for any doubt as to their being homologous organs all through 

 the three sub-orders, seeing that considerable changes in the relative position of the parts 

 of cephalothorax manifestly take place during the development of the animals, at least in 

 Phalangioidae. This is evident from the fact that in this family the eyes, which in all 

 Arachnida, nay in all Condylopoda, belong to the first segment of the head (the " procephalic 

 lobe " in Arachnida), are placed more or less closely in front of the foremost transverse 



