230 PROF. W. B. BENHAM ON AQUATIC [NoV. 3, 



the loth (or in another case the 16th) segment— a point of 

 resemblance to Pontodrilus. 



The Reproductive System. — The two pairs of testes and their 

 funnels occupy the usual position in segments x., xi. 



The spermiducal funnels are large and prominent, but are very- 

 little folded. The ducts of each side unite in segment xiii., and 

 the single duct thus formed opens into the neck of the spermi- 

 ducal gland at the junction of the latter with its muscular duct. 



The gland is tubular, undulating, and occupies segments xvii. 

 and xviii. ; its muscular duct is short, narrow, and curved, opening 

 to the exterior in segment xviii. by a very small pore. The 

 structure of the gland is similar to that normal in the subfamily ; 

 the lumen is provided with an epithelial lining of short columnar 

 cells, between which pass the necks of long, club-shaped gland- 

 cells in groups ; the layer of gland-cells is of considerable depth 

 and is covered by peritoneum ; no muscles are present till the 

 duct is reached. 



In connection with each of the male pores is a couple of long, 

 delicate copulatory chcetoe (accompanied by one or two reserves on 

 each side). Each chseta is about twice the length of a locomotor 

 bristle (PL XXVI. figs. 35, 36) and half its width ; it is nearly 

 straight, and its terminal region presents a few lateral notches — 

 which seem to correspond to the crescent-shaped furrows in the 

 normal chsetse. 



There are two pairs of sperm-sacs occupying segments ix. and 

 xi., and the intervening segment is filled with loose masses of 

 developing spermatozoa. 



The ovaries and their ducts occupy the usual position. Each 

 ovary is of considerable size and appears, in sections, nearly to 

 fill the segment ; strings of rather large ova, connected by very 

 delicate threads, even extend upwards above the gut. An ovisac 

 on each side contains eggs in which I note astropheres and 

 spindles in two or three cases. 



There are four pairs of spermatJieccB in segments vi., vii., 

 viii., ix. ; each consists of a relatively large ovoid ampulla and a 

 short, distinct, muscular duct, into which opens a small globular 

 diverticulum filled with spermatozoa. 



Dimensions. Length 35 to 40 mm. ; diameter 1 } mm. Segments 

 85 to 90. 



Locality. Lake "Wakatipu, South Island, New Zealand. 

 Remarks. — This new species difiers from the rest of the genus 

 Plutellus, as enlarged by Michaelsen to include several species of 

 Cryptodrilus and of Megascolides, in two characters, viz., in the 

 absence of a gizzard, and in the absence of nephridia from the 

 fourteen anterior segments. In both these points it agrees with 

 Pontodrilus (a sea-shore Oligochsete), and they appear to be related 

 to an aquatic habit. But in other points the agreement of this 

 species is with the genus Plutellus. 



This is the first time that a representative of this genus (on the 

 whole an Australian form) has been met Avith in New Zealand. 



