neto Genus of Oh'f/ocJia'ta. 75 



Gavclcns, from Kew ; these specimens were all carefully ])re- 

 servcd for ]nirj)Oses of section-cutting", the only method of 

 studying small worms which are not large enough for dis- 

 secting, and which are too opaque to admit of examination 

 while alive. I have invariably made longitudinal sections 

 of the anterior twenty segments or so, which I believe to be 

 much more satisfactory than transverse sections. This method 

 is equally good for the purpose of studying the histology of 

 the organs, and is of course far better than the metlio 1 of 

 transverse sections for fixing with precision the ])osition of 

 the various organs — so important a point in Annelid anatomy. 



There are not many groups of animals now in which it is 

 possible to find in a few months, and as it were accidentally, 

 four new species, constituting a well-marked new genus. 

 The fact that during the year 1890 forty-eight new species 

 and twelve new genera were described by only eight natura- 

 lists with no special facilities (except in the case of one) for 

 collecting, shows that much remains to be done before this 

 group of Annelids is anything like exhausted. And, 

 moreover, most of these new species do not differ merely by 

 some trifling external character, of no interest except to the 

 systematist, but show for the most part important anatomical 

 differences often of more than merely classificatory interest. 



The five new species, of which I give an account here, 

 were all found in the earth in which tropical plants had been 

 im])orted to the Kew Botanical Gardens. Seeing that this 

 accidental transference of worms from one country to another 

 is so easy, it behoves one to be very careful in drawing con- 

 clusions as to the geographical distribution of the group. 



I place this new genus near to Ocnerodrilus, and, on account 

 of certain peculiarities in the first species, name it Oordio- 

 drilus. 



II. Descijiption of five new Species of Gordiodrilus. 



In the following acebunt I have endeavoured to avoid any 

 unnecessary repetition ; where any organ presents exactly 

 the same structure in all species, I have only described it 

 once in detail. 



1. Gordiodrilus tenuis, sp. n. (PL VII. fig. G C.) 



The material consisted of one specimen only from Assaba, 

 on the west coast of Africa. 



The worm was during life extraordinarily thin and active in 

 its movements ; its general appearance was suggestive rather of 

 a Lumbriculid or a Pltveoryctes, particularly of the latter genus. 



