1900.] EARTHWOBMS OF THE " SKEAT EXPEDITION'." 909 



naturally suggested the specific name. The papillae in question 

 have a transverse direction and are oval in form, bearing a con- 

 spicuous slit ; they interrupt the line of setae, and correspond 

 exactly in position to the male pores. 



The male pores need no special description, as they are exactly 

 like the copulatory papillae of the nineteenth segment. As to the 

 internal anatomy, the gizzard-septum appears to be wanting. 

 Caeca are present. The last heart is in segment xii. 



The sperm-sacs are large and racemose, meeting in the middle 

 line above ; there are three pairs of them lying in segments x., xi., 

 xii. 



The spermiducal glands are large and rather ragged. They 

 occupy segments xvii.-xix. and a trifle of the adjoining segments 

 also. The duct is thin and curved upon itself in the usual horse- 

 shoe-shape. It opens on to the exterior through a not very large 

 terminal sac. In segment xix. is a similar sac, which corresponds 

 to the papilla on the exterior of the body already described. The 

 likeness between these two sacs, coupled with the external resem- 

 blances already referred to, suggests that we may have to do with 

 a species which has only recently lost the primitive double male 

 efferent apparatus. 



I have made a series of sections through this region of the body 

 in order to attempt to further elucidate the remarkable appearances 

 seen externally and on a dissection. With regard to the male 

 pores, the duct of the spermiducal gland does not open directly into 

 the terminal sac, but is prolonged into a penis-like process which 

 lies within the sac and does not extend quite so far as to its external 

 orifice ; doubtless it can be protruded. The walls of the sac are 

 much wrinkled by deep folds, the interstices between which are 

 reduced to a minimum, as the epithelium on either side is very 

 nearly in contact. It is surrounded by a layer of loosely arranged 

 muscular fibres, which in my sections (transverse to the longitudinal 

 axis of the body) are seen to run over the sac from left to right and 

 to be mingled with numerous fibres running in a longitudinal 

 direction. The actual orifice of the sac, though large, does not 

 occupy the whole of the groove upon the xviiith segment. The 

 orifices upon the xixth segment, which are externally so like the 

 male pores upon the xviiith segment, lead, like them, into a sac. 

 This sac in structure is precisely like that of the bursa copulatrix 

 of the male efferent apparatus. It has a widish mouth ; it is lined 

 by tall columnar epithelial cells, and its walls are thrown into close 

 folds. The resemblance to the bursa copulatrix does not, however, 

 end here. A penis-like process depends from the dorsal wall of the 

 sac into the interior ; I cannot distinguish this structure from the 

 penis of segment xviii., save for the fact that it has no lumen. 

 For the rest its shape, size, and relations are precisely those of the 

 penis. Instead of by a lumen its thickness is occupied by the 

 ducts of numerous unicellular glands which form a mass above the 

 sac and are surrounded by a special muscular layer. They are 

 precisely like those of other species of Amyntas. 



