f the spleen.* The pancreas is thicker 
the Echidna, and enlarges considerably to- 
ds the duodenum. 
The principal difference occurs in the place 
termination of the pancreatic duct, which, 
1¢ Ornithorhynchus, joins the ductus chole- 
us, but in the Echidna terminates sepa- 
ately in the duodenum and nearer the pylorus 
an does the ductus choledochus. 
he arrangement of the hepatic and pan- 
tic ducts is thus conformable to the Mam- 
an ype and the Ornithorhynchus, in the 
ee of the junction of these ducts near the 
mencement of the ductus choledochus, ma- 
Sts its affinity to the Marsupials, as the 
__ Same structure occurs in the Dasyure. 
. = The spleen (fig. 187, u, u) consists of two 
bent upon each other at an acute angle, 
* Meckel, loc. cit. p. 46. 
MONOTREMATA. 
Fig. 188. 
389 
Submaxillary glands, Echidna setosa. (Original. ) 
in which the Monotremes again resemble the 
Marsupials. In the Ornithorhynchus the ante- 
rior and right lobe is four inches long, the pos- 
terior and left lobe two inches and a half; the 
right lobe is bent upon itself. In the Echidna, 
besides the two lobes which are continued for- 
wards from the’left side, there is a third shorter 
descending appendage.* The lobes are thin and 
moderately broad in both Monotremes, and in 
structure, size, situation, and general figure, the 
spleen conforms to the Mammalian type, al- 
though this is exhibited under a more than usual 
complication of external form. 
CIRCULATING SYSTEM. 
Blood of the Ornithorhynchus—A Mammal 
presenting such striking resemblances in cer- 
tain parts of its organization to the oviparous 
* Cuvier, |. c. t. iv. p» 591s 
