252 SPOLIA ZEYLANICA. 



Of the four species which are already known, we are acquainted 

 with one {Aulophorus palustris) only through a short diagnosis 

 previously pubHshed by Michaelsen. Another {Limnodrilus socialis) , 

 first described a short time ago by myself, is interesting as being one 

 of the very few Tubificids kno\vn to occur in the Indian region. The 

 remaining two {Pheretima ha way ana and Dichogaster affinis) have 

 been known for some time. 



The type specimens of the new species are to be kept in the Indian 

 Museum, duplicates being sent to Colombo where possible. 



I wish here to express my thanks to the authorities of the Natural 

 History Museum, South Kensington, for very kindly affording me 

 all possible facilities in the use of their library during the writing of 

 this Paper. 



DeRO ZEYLANICA, sp. nOV. 

 (Plate I., Figs. 1-4.) 



Four specimens, one incomplete ; in the same tube as Limnodrilus 

 socialis and Aulophorus palustris. Hill country, Kandy, Ceylon, 

 1,600 feet. 



The length of a complete single animal was 7 • 5 mm. ; none of the 

 specimens were preparing for asexual division ; when this occurs the 

 length of the chains would probably be greater. Breadth, maximum 

 • 35 mm. Segments 43-60. Prostomium short, rounded. There are 

 no eyes. 



The posterior end of the animal is expanded, and in the preserved 

 specimens this expansion may either have the form of an approxi- 

 matety circular sucker-like disc, facing upwards, with a definite 

 margin, or of a deep and narrow cup, opening dorsally, and com- 

 pressed from side to side ; the latter was the case in the specimen 

 chosen for sectioning (figs. 1-3). A number of ridges can be indis- 

 tinctly seen on the inside of the cup, or on the face of the disc ; 

 some of these are more distinct than others, and in the case where 

 the posterior end of the animal is flattened they radiate towards the 

 periphery of the disc. 



A series of transverse sections is necessary in order fully to 

 elucidate the structure of this region ; the following description 

 begins anteriorly, from a point in front of the opening out of the 

 intestine into the branchial fossa or branchial funnel, and proceeds 

 posteriorly to the hinder end of the animal. 



In the specimen taken for sectioning, the whole posterior end of 

 the animal appears to have been laterally compressed. The first 

 pecuHarity to be mentioned is the occurrence, dorsal to the end 

 of the intestine, of a pocket, or forward diverticulum from the 

 branchial fossa ; at the anterior blind end of this pocket a pair of 

 gills originate, which further back lie free within the cavity of the 

 diverticulum (fig. 1). 



Proceeding backward, the diverticulum and gut shortly unite, and 

 we may now speak of the cavity as the branchial fossa. The first 



