and Classification of the Opiliones. 505 



Fain. Phalangiidje. 



Subfaiu. 1. Sclerosomatinpe. 



Sclerosoma &c. 

 Siibfam. 2. Phalangiinje. 

 Phalanyium &c. 



Fam. ISCHYROPSALID^. 



Ischyropmlis &c. 



Fain. Nemastomatidje. 

 Nemastoma. 



Fam. Tbogulid-s;. 



Subfam. Dicranolasmatinas. 



Dicranolasma, Aniojmuni. 

 Subfam. Trogulinaj. 



Troyulus, Ajielasmocephalus. 



This clas.sification, which was followed in the main by 

 Hansen (Nat. Tidskr. 1884), by Sorensen (N"at. Tidskr. 1884, 

 Term, fiizetek, xvii. 1894), Kraepelin(Mitth. Mus. Hamb. xiii. 

 189C), Becker (Arach. Belg-.),and O. P. Cambridge (P. Dorset 

 Field-Club, xi. 1890), is more in accord with the facts ; but I 

 do not think the arrangement of the genera into four equiva- 

 lent sections fully expresses their true relationships. More- 

 over, in the key to the determination of these families, they 

 are grouped under two primary headings, the first containing 

 the Phalangiidffi, and the second the Ischyropsalidaj, Nenia- 

 stomatida^, and Trogulida;, a method which suggests a covert 

 adherence to the views of affinity originally promulgated by 

 ISorensen. 



Tliat the Palpatores or Plagiostethous Opiliones fall into 

 the four families instituted by Simon is thus generally ad- 

 mitted, but that these families are naturally groupable into 

 the two sections which are also usually adopted is, I am per- 

 suaded, an erroneous view. They fall into two groups, it is 

 true, but the line of division comes, not between the Phalan- 

 giida? and Ischyropsalidae, but between the Ischyropaalid^ 

 and Nemastomidae, Ischyroi)saHs being far more nearly related 

 to Phalangium than to JSemastoma. 



This proposition, so contrary to what is usually accepted, 

 may be easily justified. 



The sternal surface of the prosoma in the Phalangiidaj is 

 furnished with a relatively large, usually longitudinally 

 oblong, anterior plate or labium^ which underlies and is 

 partially united to the maxillary processes of the legs of 

 the first pair. Behind, with its free anterior edge over- 

 lapping the posterior border of the labium, lies a second sternal 

 plate, which is shorter and wider than the first, with its long 



