A ueAv Species of Nectouemertes. 343 



charged with a darkly staining secretion. In some respects these 

 elements resemble those of the connective tissue and may in reality 

 be such since they manifest no distinct characters when treated 

 with the ordinary stains. 



The proboscis in all of the specimens has been discharged and 

 lost, but by means of sections it may be clearly established that it 

 liolds a position from a short distance in front of the brain to a 

 point about 3 mm from the posterior end of the body. The rhyncho- 

 daeum is therefore relativly short, extending from the small, nearly 

 terminal, proboscis pore slightly less than half way to the dorsal 

 commissure. Its lining epithelium throughout has been dislodged 

 and anteriorly the heavy basement membrane is thrown into several 

 prominent folds which diminish the size of the lumen to a considerable 

 degree; but in its posterior half the folds become more numerous 

 and smaller and the cavity attains a size equal to that of the 

 rhynchocoel shown in Fig. 7. Numerous longitudinal muscle bands, 

 continuations of some of the bundles of the forward end of the 

 proboscis sheath, form its walls and are intermingled with a very 

 few diagonal fibres and radial bundles which extend outward and 

 unite with the body wall. 



In the middle regions of the body a cross section of the pro- 

 boscis sheath presents the appearance represented in Figs. 11, 13. 

 The epithelium has been dislodged at most points but where it 

 persists its general arrangement and form are typical. The basement 

 layer is relativly thick and homogeneous but otherwise exhibits no 

 noteworthy characters. The layer of longitudinal muscles is thin 

 but well defined and consists of numbers of fibres arranged into 

 small bundles placed side by side against the basement membrane. 

 The outlying layer of circular muscles is considerably thicker and 

 is composed of a feltwork of fibres among which a few appear from 

 sections to hold a circular position while the remainder are diagonal. 

 Passing anteriorly, this condition of affairs continues to within a 

 a short distance of the brain wiiere some of the fibres of the inner 

 longitudinal layer become diagonal and finally merge indistinguishably 

 with an inner circular band, which originates at this point and con- 

 tinues anteriorly to the rhynchodaeum. Some of the longitudinal 

 fibres appear to be continuous with the rhynchodaeum and to a very 

 much less extent the same is true of the outer layer of circular 

 muscles which diminish in number in the region of the brain and 

 at the junction of the rhynchodaeum form a relativly inconspicuous 



