DESCRIPTIONS OF GENERA AND SPECIES 559 



Trigaster lankesteri, BENHAM. 

 T. Lankesteri, BENHAM, Q. J. M. S., vol. xxvii, p. 94. 



Definition. Clitellum, XIII-XL ; from segment XVII onward there is a ventral area free from 

 glandular modification. Prostomium not imbedded in the buccal segment. Setae strictly 

 paired. No dorsal pores. Intestine begins in XIII. Spermathecae without any apparent 

 diverticula. Hob. St. Thomas, West Indies. 



m 



Genus BENHAMIA, MICHAELSEN. 

 Syn. Acanthodrilus, AUCT. (in part.). 



DEFINITION. Setae strictly paired, absent on segment XVIII ventrally. Clitellum 

 incomplete. Two gizzards present ; calciferous glands three pairs, very distinctly 

 marked off from oesophagus. Nephridia diffuse. Two pairs of spermathecae. 

 Penial setae nearly always present. 



This genus contains a very considerable number of species, almost exactly the 

 same number as of Acanthodrilus, viz. thirty-one. The genus has its head-quarters 

 in tropical Africa, twenty-five of the species being there met with. One species 

 certainly, and another more doubtfully, are found in the New World ; three come 

 from Java and Sumatra 1 , while the single remaining species of the genus (B. bolavi) 

 appears to be almost world-wide in its distribution. In addition to the species 

 described in the present paper, I have examined a form from Trinidad, which seems 

 to be different from any of them ; it is remarkable on account of its bright green 

 colour; unfortunately, an accident in the process of preservation prevents me from 

 being able to do more than assign it to the present genus. 



Under the description of the genus Acanthodrilus (see p. 528) I have referred to 

 some of the structural differences between the two genera. The characters of the 

 calciferous glands seem to distinguish this genus from all the remaining genera 

 of the family excepting only Playiochaeta. So, at any rate, it appears from such 

 data as are to hand. The calciferous glands in those species which I have myself 

 examined are reniform pouches, pinched off from the oesophagus, and marked by 

 transverse furrows, along which run blood-vessels ; HOEST figures exactly the same 



1 MICHAELSEN is of opinion that those found out of Africa are accidental importations. 



