416 Oil the Genera Trigastcr and Benhamia. 



4. The two pairs of spermathecse lie in viii. and ix., are 



^'lobular, have no appendix or swellings or diver- 

 ticula near the external apertures^ which are placed 

 posteriorly, i. e. between viii.;ix. and ix./x. 



5. No penial setaj. 



6. No dorsal pores. 



Benhamia : — 



1. The clitellum occupies at most eight somites, varying, 



however, in extent and limits (xiii. to xix. or xiv. 

 to xxi.). 



2. There are only two gizzards. 



3. Calciferous glands are present. 



4. The sperm athecfe are rather ovoid than globular and 



have appendices or diverticula to their narrowed 

 ducts, which open externally on the anterior boun- 

 daries of their somites, viz. vii./viii. and viii./ix. 



5. Penial sette in special sacs are present in relation to the 



prostate. 



6. Dorsal pores are present, at any rate in some of tlie 



species. 



Both genera, however, agree in having all the eight setfB 

 in each somite close together on the ventral surface, in having 

 a pit or fossa, at the bottom of which the prostates and spermi- 

 ducal pores open externally, and in these two characters they 

 differ from Acanthodrilus. 



The genus Trigaster includes at present only one species, 

 T. Lankesteri^ Benham, 1886, from St. Thomas, West 

 Indies. 



The genus Benhamia includes the following species, all 

 being from West Africa, with the exception of the last, 

 the locality of which is unknown, and is merely a matter of 

 speculation : — 



1. B. rosea f Michaelsen, 1889. 



2. B. Stuhlmanni, Michaelsen, 1890. 



3. B. affinis, Michaelsen, 1890. 



4. B. Schlegelii, Horst, 1884. 



5. B. Biittihoferi, Horst, 1884. 



6. B. Beddardi, Horst, 1888. 



7. B. scioana, Rosa, 1888. 



8. B. Godeffroyi, IVIichaelsen, 1890. 



