ANODONTA — GLANDULAR SYSTEM. 
179 
end, and the two glandular parts are similarly, but more ventrally con- 
nected. The secretory limbs are also joined anteriorly to the anterior 
part of the pericardium by the reno-pericardial funnels, which open 
mthin the pericardial cavity by a pair of somewhat crescentic slits. 
Fig. 348. — Longitudinal section through the right Renal organ or Nephridium of Anodonta 
cygnea^ illustrating its relation to the pericardium and also showing its structure and the intricate 
series of connecting chambers between the glandular section and the ureter x 3 (after Rankin). 
a. auricle of the heart ; br. left branchia ; br.n. branchial nerve ; f. foot ; k. kidney or renal 
organ of right side laid open ; o.u. e.vternal orifice of right ureter ; f>.ad. posterior adductor ; 
posterior retractor ; r.f. right reno-pericardial funnel, connecting the pericardium with the glandular 
part of the kidney ; ti. ureter, showing the three complex chaml<ers intervening between the 
glandular section ; zk ventricle of the heart ; v.g. visceral or parieto-splanchnic ganglia. 
The venous blood on its way to the branchi;n from the vena-cava 
circulates within an intricate renal plexus, the renal cellules during the 
passage of the blood through the organ eliminating the nitrogenous 
waste matters in the form of urea, uric acid, etc., which are ex2)elle<l 
from the system by the right and left ureters, which terminate in a 
' pair of small outwardly du’ected orifices with prominent whitish 
margins, opening respectively into the right and left exhalent chambers 
and always placed above the cei’ehro-pleuro-visceral commissure. 
/ 
Fig. 349. — Dorsal view 'of Anodonta cygnea to show the position and aspect of the organ of 
Keber or pericardial gland (after Grobben). 
a.ad. anterior adductor ; a.r. anterior retractor \f. foot ; p.ad. posterior adductor ; p.r. posterior 
retractor ; fc.gl. pericardial gland, the four anteriorly placed symmetrical scars are indications 
of the anterior umbonal retentor muscles. 
The Pericardial Glands or Keber’s organs are rusty-red, paired 
glandular proliferations of the anterior epithelial walls of the peri- 
cardium which have an excretory function analogous to that of the 
