78 H. J. FLEURK. 



card. The structure on the left of the pericardium is a small 

 sac, whoso walls contain, in parts, lymphatic tissue; it is 

 doubtfully renal in function, and is called the papillated sac. 

 That on the right side is the functional kidney, and it 

 possesses various large lobes, including a long anterior 

 one (a. l.) stretching forward on the left flank of the great 

 shell muscle. All workers also find two openings at the back 

 of the mantle cavity : one (1) placed definitely on the left side 

 of the rectum, the other (2) further towards the right. 



Von Jhering (1), Perrier (6), and Wegmann (4) consider 

 that the right opening (2) is the orifice of the functional 

 kidney (7e), and the left one (1) that of the reduced left 

 kidney (7 l) or papillated sac. They state that the gonaduct 

 (from 6 e) opens into the right kidney (7 r). Haller (9) 

 found that the right kidney (7 r) communicated with the 

 other (7 l), and that both opened by the orifice (1) of the 

 left kidney, the right orifice (2) belonging solely to the 

 gonaduct. My observations on these points agree with those 

 of Perrier, who also worked with Haliotis tuberculata. 

 Haller used H. glabra, and it would be necessary to study 

 that species before rejecting his statements. Perrier, Weg- 

 mann, and Erlanger (8) described a pericardial communica- 

 tion for the papillated sac, but not for the functional kidney ; 

 while Haller found a funnel opening from the pericardium 

 into the right kidney, but was unable to discover an internal 

 orifice to the papillated sac. The former result has been 

 generally accepted, and it is quoted as evidence that the 

 right kidney is really degenerating in the Rhipidoglossa, and 

 that the kidney surviving in Monotocards is therefore the 

 Diotocard left (7l). The methods adopted by these authors 

 were the usual ones of dissection, injection, and section 

 cutting, but in this case there seems to be another line of 

 investigation. It is well known that the Diotocard female 

 liberates her ova in an irregular fashion a few at a time into 

 the mantle cavity. Now, if the gonaduct communicates with 

 the kidney, ova might be found at a certain season in the 

 cavity of the latter; and, further, if this kidney has a peri- 



