NEW SPECIES OF OCNERODRILUS. 235 



beyond the point of the beginning of the oesophagus in 

 somite ii. A beautiful vascular network is interspersed 

 between the muscles and in the glandular mass, origin- 

 ating principally from the lateral vascular trunks coming 

 from the diverticula of the oesophagus. Only with a 

 very strong staining of eosine do these minute vessels 

 become clearly visible (fig. 2, v.). 



The oesophagus consists of along, comparatively narrow 

 cylindrical duct, beginning at the boundary between 

 somites i and ii, and extending to the diverticula in 

 somite ix. Its inner epithelial walls are much folded. 

 Exteriorly the oesophagus is of even width, neither con- 

 tracted nor swollen at the septa nor at the place where 

 the diverticula enter it. In Ocnerodriltis Eise^ii, lately 

 described by Beddard, the esophagus appear to be con- 

 siderably enlarged at the junction with the diverticula. 

 In Ocnerodrilus Rosce the swelling is somewhat less, but 

 in other species it is almost entirely wanting. If this 

 character is constant, or if it changes according to the 

 contractions of the worm, remains yet to be seen. 



Diverticula of cvsophagus. In somite ix the oesopha- 

 gus is furnished with one pair of diverticula, or pouches 

 resembling the calciferous glands in other genera. These 

 diverticula are found in all the species of the genus, they 

 vary a little in form, and are of various lengths, accord- 

 ing to the state of contraction, and are hardly constant 

 enough to be used as species characteristics, although in 

 different species a difference in form may be noticeable. 



The pouch in Gordiodrilus which is median and single, 

 differs considerably from the corresponding, but paired, 

 organ in Ocnerodrilus. In the former genus the blood 

 vessels traversing the pouch form a network, or at least 

 anastomose with each other, which is not the case in 

 Ocnerodrilus. In the various species of the genus the 



