114 THE VOYAGE OF H.M.S. CHALLENGER. 



blood-space (archicoelome) surrounding it, I did not succeed in demonstrating oue. Con- 

 sidering that I had found such openings in Carinoma, and that Oudemans had afterwards 

 demonstrated them in Carinella, I expected they would also be present in Carinina. 

 For the present, however, the result of a very attentive search is that they are absent ; at 

 least no opening is visible which can be said to prove a similar communication beyond all 

 doubt and by which it might be demonstrated once for all. Questionable points of 

 communication, which might eventually be interpreted as such, I have not allowed to 

 influence my testimony, so that, for the present, I must answer the question in the 

 negative. The case stands in a similar light with respect to the Schizonemertea and 

 Hoplonemertea, as will be seen hereafter. 



If this communication with the blood-spaces is thus not demonstrated, that with the 

 cavity of the second part of the nephridial system is subject to a much less degree of 

 doubt ; and though I did not actually see the lumen at the point of communication, I did 

 see the communication itself as represented in fig. 4. It is then seen that this second 

 portion is distinguished from the one just mentioned by the presence of a spacious cavity. 

 This cavity, which may be called the nephridial canal, is first found ventrally to the 

 glandular spongy portion (figs. 4-6), but then gradually bends upwards as it passes 

 further backwards along the animal, until it becomes a narrow channel with a very 

 distinct and ciliated epithelium (figs. 1, 2), which passes at a very strongly inclined angle 

 (fig. 1) through the successive muscular layers, then makes a very sharp bend towards 

 the exterior surface, and traversing also the basement membrane and the integument, 

 opens on the exterior. This exterior opening has not been figured, but is found 

 in the sections following upon that which is represented in fig. 1. The two exterior 

 openings of the nephridial system lie on the dorsal surface of the animal, and at the 

 same time mark the point where the nephridial system reaches furthest backwards, the 

 glandular portion of it stretching forwards towards the head. That this nephridial canal 

 may, at all events in its proximal part, be more or less folded, is seen both in figs. 4 and 

 5, Nc, in the latter figure the lumen having an appearance as if it were doubled. 



The nephridial system of our second Challenger genus of Pakeonemertea, Eupolia, is, 

 as was already known from Oudemans' researches, more comparable to that of the Schizo- 

 nemertea than to that which has just been described in Carinina. It offers certain 

 peculiarities which deserve special mention. Here, too, we may distinguish, as we may 

 throughout the whole class of the Nemertea, longitudinal and principal nephridial ducts 

 situated in the blood-spaces or enclosed by the gelatinous tissue (Hoplonemertea), and 

 transverse or deferent ducts placed perpendicular to the foregoing, varying in number 

 and somewhat in size, and brineing about a communication between the ducts before 

 mentioned and the exterior. 



Of the aspect and situation of these two portions in a transverse section, a comparison 

 of figs. 9 on PI. VI. and 3 on PL VII. may convince us. Each of them represents 



