1904.] EARTHWORMS FROM NEW ZEALAND. 239 



alteration in the definition of this genus. But tliis, it seems to 

 me, is a better plan than to modify the diagnosis of Mlcroscolex, 

 for the latter is an American genus, though one species *" at least 

 has been recorded from New Zealand ; whereas the only species 

 of Rhoclodrilus hitherto described are from this region. 



The genus, originally founded by Beddard ('89) for^. minutus, 

 has suffered from its resemblance to Microscolex. Originally 

 distinguished from it by its author, as haAdng the prostate pore 

 separate from the male pore, it was, later, included in that genus, 

 on the discovery that the same arrangement is true of certain 

 species of the older genus. Michaelsen ('00), however, retains it 

 as distinct, owing to the fact that Rh. minutus has four pairs of 

 spermathecse. 



In 1900 I described a w^oi-m from the Chatham Islands as 

 " Microscolex Mtttoni" with two pairs of spermathecfe, followino- 

 Beddard in disallowing Rhoclodrilus. But since the publication 

 of that article I have studied a species from Campbell Island 

 and the Lord Auckland Group, in which there are three j^airs of 

 spermathecfe. 



Now all these worms agree with the two species described in 

 the present article in having an elongated jirostate, extending 

 through several segments, and in most of them the gizzard is well 

 developed ; the clitellum saddle-shaped. But the position of the 

 last heart is not constant. 



The size of the worms, too, exceeds that of the species of 

 Microscolex. 



I therefore agree with Michaelsen to resuscitate Beddard's 

 genus Rhododrilus to include our New Zealand woi'ms but 

 regard the form and extent of the prostate as the chief character, 

 and one that readily distinguishes it from Microscolex. 



The characters of the genus as thus modified may be defined as 

 follows : — 



Chfetse 8 per segment, more or less widely spaced. Nephridio- 

 pores not alternating ; male pores on 1 7 ; prostate pores one paii', 

 in 17, opening close to the male pore. Clitellum saddle-shaped, 

 occupying 4 to 6 segments, 13 (14) — (17) 18, A gizzard in 5. 

 Testes two pairs. Prostates tongue- shaped, elongated, more or less 

 undulatori/, extending through 4 io 8 segments. Penial cha?tje 

 present. 



Distribution. New Zealand and neighbouiing islands, 



1. Rh. mimttus, Beddard, 1889. South Island. 



2. Rh. huttoni, Benham, 1900. Chatham Island. 



3. Rh. edulis, Benham, sp. n. North Island. 



4. Rh. besti, Benham, sp. n. North Island. 



I have specimens of other species in my possession of which a 

 description has not yet been published. 



* Of a second species, M. monticola, our information is not altogether sufficient 

 to permit us to make use of its characters in this discussion. 



