180 THIRTY-FIFTH REPORT ON THE STATE MUSEUM. 
fig. 5). The dorsal margins of the outer palpi are attached to the 
inner face of the mantle, that of the inner laminz to the foot. The 
outer and inner palpi of each side of the animal are united along a 
line designated by dots on fig. 6, Pl. 13. The outer faces of the 
lamin are smooth and consist of a thin layer of epithelium ; the 
inner faces, for two-thirds the length from the posterior portion, are 
strongly ridged transversely ; the free edges of the palpi being crenu- 
late. There are about eighteen ridges in the space of five millimetres. 
The summits of the ridges have comparatively large vibratile cilia (Pl. 
13, fig. 7). Ata point two-thirds of the length of the palpi distant 
from the posterior ends the transverse ridges abruptly terminate, and 
from that point to the mouth the ridges are irregular and longitudinal, 
also ciliated. When the animal is living the inner face of the outer 
palpi and the outer face of the inner palpi are slightly distant from 
each other. The current of water which contains the minute animal 
and vegetable substances constituting the food of the Anodonta, is by 
the cilia of the transverse ridges of the palpi carried toward the 
mouth, and by the action of the cilia of the longitudinal ridges di- 
rectly to the mouth, and then by the cilia of the lining membrane of 
the oral cavity and short esophagus, to the stomach. 
THE LIVER. 
(Plates 4, 6.) 
~ The liver invests the stomach (PI. 6, fig. 1, 1.), and consists of a 
greenish brown sponge-like mass, formed of cxca or tubes arranged 
in racemose clusters, and communicating with the stomach by means 
of minute orifices ; the czeca or tubes (Pl. 4, figs. 7, 11) are lined with 
epithelium cells. 
The liver is abundantly supplied with blood and from the blood the 
cecal tubes extract a fluid which resembles the bile of animals of 
higher organization, which fluid enters the stomach by means of the 
orifices previously mentioned, and aids in the process of digestion. 
THE RENAL ORGAN. 
(Plate 9.) 
The renal organ, or organ of Bojanus is situated immediately below 
the pericardium. It is thus called after the name of its discoverer, 
Bojanus. This name has not been universally adopted and I shall use 
the term renal organ as being more appropriate. 
The renal organ consists of two symmetrical lateral parts. Each 
part is separated into two chambers, the upper and the lower. 
The upper is the smaller and known as the non-glandular or pleural 
