.] DR. A. G. BOURNE ON INDIAN EARTHWORMS. 



663 



I regret that in some cases I was unable to render ray observations 

 complete, owing to want of sufficient material. It seems, however, 

 desirable to publish this preliminary note even though it is in some 

 cases incomplete, as more thorough investigations in any particular 

 locality may be considerably delayed. The greater number of forms 

 belong to the genera Perichceta and Moniligaster, and for the 

 present I deal with these only. I have found, in addition to these, 

 two species of Lumbricus at great elevations at Ootacamund and 

 Coonoor. One of these presents a clitellum extending over somites 

 xxvii.-xxxiv., and the other over somites xxx.-xxxiv. I refrain from 

 naming these until I can characterize them more fully. I have also 

 some worms belonging to other genera, but with the scanty hterature 

 to which I have access 1 cannot say whether they are new genera 

 or not. 



Had it not been for Mr. Benham's' most useful resume of known 

 Earthworms, I should have been able to do far less than I have done. 

 Where I have given measurements or counted the somites I have 

 chosen the largest individual I could find. 



PERICH^TIDiE. 



The Perichaetidse are characterized by the fact that each somite 

 bears numerous setae arranged in a more or less complete ring. 



The genera which are at present included in the group are :— 

 Perichceta, Schm.; Megascolex, Temy). (Pleurocheeta, Bedd.); Peri- 

 onyx, E.P. ; and Rhodopis, Kinb. 



These genera are at present distinguished one from the others, 

 thus : — 



PericktEta presents a clitellum in somites xiv., xv., and xvi., a pair 

 of laterally-placed male pores in somite xviii., and very numerous 

 equidistant setae. 



Megascolex presents 100 setae arranged in a ring, but with a dorsal 

 break. 



Perionyoc presents a clitellum in somites xiii., xiv., xv., xvi., and 

 xvii., a pair of male pores placed in a median pit in somite xviii., 

 and 30 equidistant setae. 



Rhodopis presents a clitellum in somites xii. and xiii., a pair of 

 male pores between somites xiv. and xv., and 50 to 60 equidistant 

 setae. 



Now let us consider these characters in relation to the worms 

 described below. Among these we find that there are numerous 

 intermediate conditions, in respect to the arrangement of the setae, 

 between an almost equidistant series and a series presenting consider- 

 able dorsal and ventral gaps'. Secondly, in one form there are two 

 pairs of m ale pores (P. stuarti) . Lastly, with regard to the extent of 

 the clitellum, in the form which I have referred to Perrier's genus 

 Perionyx it extends over three somites instead of five, while among the 



1 Quart. Journ. Microsc. Sci. vol. xxvi. n. b. 



2 By the terms ventral and dorsal gaps I mean the space between the two 

 most ventral and dorsal setae respectively. An ordinary gap is the space between 

 any other two contiguous setse. 



