REPORT ON THE NEMERTEA. 113 



present. This was found by me in the nephridial system of Cariyioma, and these nephridia 

 thus establish a communication between the internal blood-spaces (archicoelome) and the 

 exterior. In other genera, Carinella excepted, similar internal communications were, 

 however, sought for in vain. A very notable and exhaustive contribution to our 

 knowledge of the Nemertean nephridia was then furnished by Oudemans (XXVIl), and the 

 Challenger material, which was partly made subservient to that publication, only furnishes 

 a few additional data here worth recording, most of the peculiarities having been already 

 mentioned by Oudemans. I hold it to be one of the principal results arrived at by this 

 author, that he definitely demonstrated the presence in numerous species of Nemertea of 

 a very large number of exterior openings, connected by short transverse branches with 

 the principal and longitudinal canals of the nephridial system, and that, at the same 

 time, he noticed that these transverse canals were paired and opposite, and showed an 

 arrangement which might most assuredly be compared to an incipient stage of metamery 

 in the nephridial system. 



This fact is most distinctly borne out by the Schizonemertea. The Palgeonemertea 

 (at any rate the Carinellidse) and Hoplonemertea show an arrangement which presents 

 different features, although, again, certain Hoplonemertea {Am])hipoms lactijloreus) 

 answer very weU to the Schizonemertean type. 



A very remarkable form of nephridia is found in Carinina grata. The two fragments 

 of this species that form part of the Challenger collection both contain this important 

 structure in toto, so that I am able to figure both transverse and longitudinal sections. 

 These figures are brought together on PI. IV., and will first have to be discussed. Two 

 portions may be distinguished in the nephridia of Carinina : in the first place, a glan- 

 dular canalicular portion in which numerous dehcate tubes appear to be closely applied 

 together into a larger lobulate mass, which is situated right and left in the blood-space, 

 not being freely suspended in it, but applied on one side against the muscular layers 

 (figs. 5, 6), and on the other side, offering a free surface towards the cavity of this blood 

 space. PI. IV. fig. 4 gives a more enlarged view {Nsp) of a longitudinal section through 

 this portion of the nephridial apparatus, and, at the same time, enables one to judge of 

 its extension, the whole of this glandular spongy portion having been reached in 

 this section. It is, of course, also present in other sections, but does not stretch either 

 further forwards or backwards. 



The furthest blind ends of the anterior caeca of the digestive canal are found to jDene- 

 trate between the lobes of this glandular mass {Jc, fig. 4). These lobes are, moreover, 

 subdivided by bundles of muscle-fibres detached from the inner circular layer (fig. 5), 

 against which the whole apparatus is so closely applied (fig. 4, Cm). The cells composing 

 the glandular portion are filled with a granular protoplasm, and have very distinct large 

 nuclei. However much I have looked out in my different sections for a definite opening 

 by which the canalicular system here described might enter into communication with the 



(ZOOL. CHALL. EXP. PART LIV. 1887.) Hhh 15 



