230 MAUTIN F. WOODWARD. 



leucocytes. The whole papilla is covered by an epithelium 

 whose cells are somewhat conical ; the free expanded bases of 

 these cells are crowded with yellowish granules, which, since 

 they are also seen in some of the leucocytes, are probably 

 waste matter taken up by phagocytes in different parts of 

 the body, and carried to the papillary sac to be discharged. 



The right kidney is very lai'ge and complicated, and 

 probably forms the more important excretory organ, beside 

 serving to transmit the genital products. This kidney opens 

 into the mantle-cavity through a glandular tube, which, from 

 a situation to the right of, has now come to lie almost ven- 

 trally to the rectum. This thick-walled glandular tube passes 

 behind into a thin-walled funnel-shaped structure, which 

 may be termed the ureter (?<.), but is really the commence- 

 ment of the kidney-chamber {k. c.) ; this passes back beneath 

 the pericardium, and enlarges behind this structure to form 

 a wide chamber with thick walls, the posterior portion of the 

 right kidney (_p. r. Ic). The walls of this chamber project into 

 the cavity in the form of a series of deep semilunar folds, 

 covered with glandular epithelium and richly supplied by a 

 plexus of blood-vessels containing venous blood. This, 

 however, only forms a part of the right kidney, a very large 

 portion running forward below the floor of the mantle-cavity 

 between the crop and the intestine as far forward as the point 

 where the brown tint stops, and marked a. r. h., fig. 7. We may 

 speak of this portion as the anterior lobe of the right kidney 

 (figs. 23, 25, and 26, a. r. h.) ; its cavity communicates with the 

 kidney-chamber near the anterior boundary of the pericardium. 

 Like the posterior lobe it is richly supplied with venous blood, 

 since it receives all the blood coming from the anterior part 

 of the body and from the foot on its way to the gills. 



The right kidney has thus a vei-y complicated form, and 

 one that will be best understood by an examination of the 

 diagrams given in figs. 25 and 26. 



The Genital Organs. — Of the three specimens examined 

 two were females and the third a male. The genital gland, 

 which presents a similar appearance in both sexes, forms as 



