40 Lyriform Organs 



of tarsus. We believe that these characters hold good for the whole order and the three sub- 

 orders respectively ; but as we have as yet examined but a limited number of representatives, 

 we have refrained from inserting our results as characters in the systematic table which we 

 propose to give below, and content ourselves with drawing attention to them here. 



Hansen has described (b, pp. 197, 198) some hairs of extremely complicated structure 

 found in varying number on palpi in Nemastoma^, and also some not less remarkable pencils 

 of microscopic hairs found on metatarsus and some of the proximal joints of tarsus of the first 

 three pairs of legs in the male Phalangium parietinum de Geer. 



Lijriform Organs'-. Gaubert was the first who, in 1892, pointed out the occurrence in 

 Opiliones of the remarkable organs of sense, formed like buttonholes, which he called lyriform 

 organs, because in Aranese, where they are found in great numbers, they are very often 

 placed together in regular groups, distantly recalling the figure of a lyre. Gaubert examined 

 particularly Phalangmiu opilio L. and found such lines or fissures on the basal joint of 

 antenna? as well as on coxa and femur of the legs. In Trogulus he found them on the same 

 parts of the legs ; but he did not describe them here more particularly. In 1893 Hansen 

 (b, pp. 192 — 196) studied the distribution of the organs both in Phalangium opilio L. and 

 particularly in Nemastoma lugubre. In this latter species they occur, according to his account, 

 on cephalothorax, on all abdominal segments, both on the tergites and sternites, except on 

 the median ventral piece of corona analis ; furthermore on the first and second joints of 

 antennae, on the mandibles, on the trochanterial as well as the femoral and tarsal parts 

 of their palpi ; finally on coxa, trochanter, femur and the last tarsal joint of the locomotory 

 legs. It is only on the limbs that several lines are to be found near to each other, and 

 they are found collected into real groups only on trochanter of the legs and on palpi ; but 

 even in these there is no really regular grouping of them, such as is seen on the walking 

 legs of Aranese. In Phalangium opilio the number of lines is somewhat smaller, but 

 they occur nevertheless in most of the places where they are found in Nemastoma, and the 

 principal difference seems to be that they are wanting on tarsi of legs and palpi. To this, 

 however, we must now add that a solitary transverse line is to be seen on the upper surface 

 and a similar one on the under surface, of the penultimate joint of the two branches of ovipositor 

 in Phalangium opilio, Leiobunum 7-otundum, Gagrella minax and Sclerosoma monoceros, and there- 

 fore probably in all Phalangioidse. On one specimen of Phalangium opilio we found, instead 

 of four solitary lines or fissures, four groups of such, containing each from two to four fissures. 

 In the other families of Palpatores we have not found any lines on ovipositor: as, however, 

 those which we have examined had not been previously cleaned with caustic potash, we do 

 not feel able positively to deny the presence of lines on them. 



' Accoriling to Simon (b, pp. 292, 306) similar hairs are such fissures of different length are arranged rather close 



found on pal^ji in Amopauin Sorensenii Thor. and Trogulus together, forming an irregular group ; on the limbs of Aranese 



aciuaticus E. S. such groups are found, in which the lines stand in regular 



- The function of these organs of sensation is not known. order side by side, and which at the same time exhibit a 



An inspection, for instance, of the abdominal tergites in a peculiar appearance on account of the lines diminishing in 



Thebjphoniis reveals on each of them a small number of lines, length from one side of the group to the other, sometimes 



which when examined by transmitted light appear like sharply also by a gradually increasing curvature and by the distribu- 



cut fissures which almost entirely penetrate the skin. In tion of the places where the nerves terminate. It is with 



each of these fissures a very small dilatation is found of a reference to these groups that Gaubert proposed the appellation 



peculiar shape and nerves are seen terminating at this point. "lyriform organs," which has since been extended so as to 



In certain places on the walking legs of Thelyphomis several apply also to single isolated lines. 



