146 DR. K. W. VERHOEFF ON BRACHYCHAETEUMA, 



possess the greatly developed bristles on the abdominal seg- 

 ments, the tarsal sucker-discs of the male, and the specialised 

 structure of the eighth pair of legs. The resemblance in 

 regard to the three-jointed posterior gonopods, which appears 

 even in the fusion of coxa and pre-femur, is also accompanied 

 by important differences which will be dealt with later. The 

 Heterolatzeliidae and Neoatractosomidse are separated by their 

 possession of tarsal sucker-discs, by the form of the abdominal 

 segments and of the copulatory organs. The posterior gono- 

 pods are never three-jointed, the anterior always essentially 

 differently organised, with pseudoflagella, graphise, or with 

 loosely attached syncoxal joints and very small telopodites. 



Most of the Craspedosomidse differ from Brachychaeteuma 

 in the form of the segments, and usually also in the possession 

 of cheirites on the anterior gonopods. When the latter, how- 

 ever, are not present, other and equally striking differences 

 are found, as for example leg-like posterior gonopods, or pro- 

 cheirites on the anterior gonopods. In any case no genus in 

 this extensive family is known which could be placed in near 

 relationship to Brachychaeteuma. 



Finally I have the Anthroleucosomidae to consider. The 

 genera of this family agree with Brachychaeteuma both in 

 general form and in the absence of tarsal sucker-discs. 

 Anthroleucosoma approaches Brachychaeteuma also in the 

 absence of ocelli and in poverty of pigment. But here also 

 both pairs of gonopods show such a fundamental difference 

 of organisation that there can be no question of any near 

 relationship. In the anterior gonopods, for example, the 

 syncoxite is absent, whilst the posterior gonopods are only 

 one-jointed, and spring from a strong sternite which bears a 

 , conspicuous median process. The Anthroleucosomidae are 

 further distinguished from Brachychaeteuma in the fact that 

 the sperm appears in egg-shaped masses. 



In spite of these differences I must place the genus Brachy- 

 chaeteuma nearer to the Anthroleucosomidas and Mastigo- 

 phorophyllidae than to any other family. One might be 



