.358 Records of the Indian Museum. [Vol. XIII, 



deferentia open in common with the ducts of the anterior pair of 

 prostates. One unpaired female pore. Two pairs spermathecae 

 with apertures on viii ; accessory glands in the neighbourhood. No 

 penial setae ; displaced and modified setae on one or more of seg- 

 ments vii, viii, ix. 



ON OTHER SUPPOSED SPECIES OF THE GENUS 

 HOPLOCHAETELLA . 



In 1909 Michaelsen (13) united with the genus Hoplochaetella 

 as defined by him (Acanthodriline arrangement of posterior male 

 organs, setae in rings, micronephridia) three species of worms 

 originally described by Benham from New Zealand, — Plagiochaeta 

 rossii, P. ricardi, and P. montana (the last two however with an 

 element of doubt, owing to the fact that Benham had revised his 

 earlier statement concerning the nephridial system). 



Plagiochaeta is a genus of the subfamily Acanthodrilinae of 

 which the type was described by Benham in 1892 ; the originally 

 paired setae have undergone the perichaetine increase, the poste- 

 rior male organs have the original Acanthodriline arrangement, the 

 testes and funnels are enclosed in testis-sacs ; the type of the genus 

 is meganephric, with nephridiopores alternating in position in suc- 

 cessive segments ; there are penial setae, and the gizzard is rudi- 

 mentary. Benham (4) subsequently described four new species ; 

 three of these were micronephric, but he did not at the time con- 

 sider this peculiarity sufficient to warrant a generic separation. It 

 was these three species which Michaelsen, with different views on 

 the value of the nephridial condition, united with Hoplochaetella. 



Benham, however, had already found that two of the three 

 species were in reality meganephric (5) ; but this Michaelsen had 

 not been willing to accept at its full value ; he did so afterwards for 

 P. ricardi, and Benham has since shown that his statement regard- 

 ing the presence of meganephridia was correct also for P. montana. 

 This leaves only P. rossii to be added to the genus Hoplochaetella 

 (Benham and Cameron, 6). 



Now the type of the genus Hoplochaetella is Perichaeta stuarti, 

 and if my former arguments are correct, Plagiochaeta rossii differs 

 from Hoplochaetella in two of the three points of cardinal import- 

 ance, — setae, nephridial condition, and arrangement of posterior 

 male organs. It cannot then go into, or even very near, Hoplo- 

 chaetella, and it is necessary to separate it under another name as 

 a new genus I may add that while the general facies of Peri- 

 chaeta stuarti agrees, so far as can be judged, with that of the 

 species which I describe below as Hoplochaetella, there is nothing in 

 the original description of Plagiochaeta rossii to remind us of Peri- 

 chaeta stuarti ; in Plagiochaeta rossii the prostates are confined to 

 their proper segments, in which they are coiled into a ball, the sper- 

 mathecal ducts have groups of botryoidal diverticula, and there are 

 prominent porophores with spermatic ridges leading from the ante- 

 rior to the posterior prostatic pore of each side. 



