Benham. — Earthioonns from Little Barrier Island. 249 



and Auckland Islands, as well as on both the main islands of 

 this area. 



It is too early at present to draw any conclusions, for we 

 must wait for further supplies of worms from elsewhere in the 

 North Island. I may, however, remark that, so far as our 

 knowledge goes, Rhododrilus is a commoner genus in the North 

 Island than in the South, where it has only been met with 

 once (Rh. minutus). It is surprising that no species of Tokea 

 have been received from the Little Barrier Island. 



I am endeavouring to trace out the line of junction 

 between the northern and southern fauna, and am satisfied 

 that it lies somewhere towards the south of the North Island ; 

 and, so far as my observations have gone, this line coincides 

 in a most remarkable manner with the line recognised by Dr. 

 L. Cockayne separating a northern and more southern flora, 

 that line being the parallel 38° S. " The northern region is 

 specially characterized by Malayan and Australian elements, 

 which we may term ' subtropical ' " (letter from Dr. Cockayne). 



Thanks to the kindness of Messrs. G-ibbs, Buchanan, and 

 others. I have received a fairly representative supply of 

 worms from Nelson : they all belong to the genera Maori- 

 drilus, Plagiochceta, Octochcetus, and Dinodrilus. Further, from 

 Stephen Island, in Cook Strait, I have obtained species of 

 Maoridrilus and Octochcetus. The specific identifications of 

 these worms I have not yet worked out, but the genera are 

 all characteristic of the South Island. From the neighbour- 

 hood of Wellington I have received a species of Maoridrilus 

 and of Neodrilus from Professor H. B. Kirk, in addition to the 

 Octochcetus michaelseni described by me in the " Proceedings 

 of the Zoological Society " (1904. vol. ii, p. 225). 



1. Rhododrilus parvus, n. sp. 



I received three specimens, which reached me alive, packed 

 in damp moss. Only one of them is mature. 



Colour. — When alive the thin body-Avail is translucent, 

 and, except for the blood-vessels, without colour, so that the 

 opaque white ccelomic fluid is visible. When preserved the 

 worm is, of course, white. 



Dimensions. — In comparison with the other members of 

 the genus recently examined by me this is a small form. 

 These three individuals measure from 55 mm. by 3 mm. (in 

 alcohol) to 65 mm. by 2 mm. (in formol). The latter contains 

 120 segments, which are annulated. 



The chcetal formula is ab = cd < be ; aa = be ; dd = 2ab. 



The clitellum occupies segments 14-17. 



The male fores are in small papillae in line of b. 



