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XL — Anatomical Description of Two New Genera of Aquatic Oligochwta. By Frank E. 

 Beddard, M.A. (Oxon.), F.Z.S., Prosector of the Zoological Society of London, 

 and Lecturer on Biology at Guy's Hospital. (With Three Plates). 



(Read December 1, 1890.) 



At present our knowledge of the exotic genera of the aquatic Oligochseta is not very 

 far advanced. During the last twenty years there has been a considerable accumulation 

 of descriptions of exotic Earthworms, but the lower Oligochseta have been much less 

 studied. The principal investigations into this group have been carried on by Eisen, who 

 has made us acquainted with a number of interesting forms, belonging to the families 

 Tubificidse and Lumbriculidse, from North America. Other naturalists, such as Leidy, 

 have also dealt with the Oligochsetous fauna of that country ; but their papers have 

 chiefly had for their object the discrimination of genera and species, and are not so much 

 concerned with the description and delineation of anatomical structure. Beyond the 

 series of papers published by the above-mentioned authors, we have only a few scattered 

 memoirs by other writers upon exotic species of " Limicolous " Oligochseta. 



Having recently been awarded, by the Government Grant Committee of the Eoyal 

 Society, a sum of money to assist me in the investigation of the Oligochseta, I have been 

 anxious not to limit myself to Earthworms, but to obtain as many specimens of the 

 aquatic forms as possible. In the following pages I describe two new genera from New 

 Zealand, and I hope to be able to offer to this Society later an account of the genus 

 Ocnerodrilus, of which I have received living examples from British Guiana. 



DESCRIPTION OF PHREODRILUS SUBTERRANEUS, nov. gen. n.sp. 



Concerning the locality and habits of this worm, Mr W. W. Smith of Ashburton, 

 New Zealand, to whom I am much indebted for two specimens, writes as follows : — 



"The two examples of the subterranean species came up in the water of a well near 

 here. They are occasionally pumped up from various depths, according to the depth the 

 pipe is driven to reach the ' flow.' Their habits at great depths in the shingle of the 

 Canterbury Plains must be very remarkable, as all their motions are peculiarly snake- 

 like, and they are extremely nimble and rapid in moving through the water." 



The worms are described by Mr Smith as being of a " fleshy red " colour during 

 life. Each measures about 2 inches in length ; even when preserved they have a 

 graceful appearance, due to the delicate, almost transparent, body walls, and to the pro- 

 jection of the long setse of the dorsal rows. 



VOL. XXXVI. PART II. (NO. 11). 2 T 



