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Mr. A. Sedgwick. 



[Dec. 8, 



gland, and expressly states that he was not able to make ont its 

 opening or relation to other organs. Schiff,* ten years later, was 

 unable to find this gland in Chiton piceus, and throws doubt on Mid- 

 dendorff's interpretation of its function. 



Von Jehringf has comparatively recently recorded some observations 

 on the kidney of Chiton, and starts from the position that no kidney 

 is known in Chiton, Middendorff's view as to the nature of the 

 branched gland having been sufficiently refuted by Schiif's later 

 observations. Von Jehring states that in the species of Chiton observed 

 by him, the kidney consists of a branched gland lying ventral to the 

 rectum in the hinder part of the body cavity, and that it opens by a 

 single median pore ventral to the anus. He further figures this 

 opening. 



While staying at Herm this summer I found a fair number of a 

 good-sized species of Chiton — Chiton discr&pcms ; and the results which 

 I have obtained from the study of the anatomy of this form, especially 

 those which concern the kidney, seem to me sufficiently important for 

 immediate publication. In the first place, I may mention that I have 

 seen nothing in any of my dissections or sections which in the least 

 supports von Jehring's statements as to the existence of a median renal 

 duct and opening ; and that my observations are entirely opposed to 

 the conclusion arrived at by this investigator as to the unpaired nature 

 of the kidney of Chiton. On the contrary, Middendorff's observations, 

 so far as they went, were perfectly correct. The paired lateral branched 

 gland described by the latter observer is part of the kidney. 



The kidney of Chiton is a paired gland with paired openings into 

 the pallial groove and into the pericardium, and is constructed on the 

 type always found in molluscan renal organs (fig. 1). It opens in the 

 species I have chiefly examined {Chiton discrepans) into the pallial 

 groove (fig. 1, r.o.) internal to, but on a level with the last gill (16). 

 The duct runs from the opening round the outside border of the 

 pallial nerve (fig. 2, r.o.), and then passes inwards to open into a 

 bladder-like structure placed in the body cavity (fig. 1, D, and fig. 2, D). 

 This bladder-like structure lies close to the body wall immediately 

 beneath the pericardium (fig. 2, p.c), and it does not seem to extend 

 backwards beyond the last gill. 



On a closer examination by means of sections, it is seen to be 

 beset by a number of branched glandular caeca, lying in the hinder 

 part of the body cavity (fig. 2, h.t.), which open into it, and into a 

 backward prolongation from it (fig. 1, h.h.). These branched glandular 

 cseca on opening the body cavity are seen as a mass of tubes apparently 

 interlacing with those of the opposite side, and lying ventral to the 



* Schiff, " Zeit. f. Wis?. Zoo!.," Bel. ix. 

 f " Morphol. Jahrbucli," Bd. iv. 



