ON THE ANASPIDACEA, LIVING AND FOSSIL. 529 
are arranged in four lateral longitudinal bands constricted 
intersegmentally. 
The blood-corpuscles appear in sections as oval cells of 
varying size, but generally with similar nuclei, Above and 
to the sides of the cardiac division of the stomach there is a 
conspicuous mass of tissue with crowded darkly staining 
nuclei and without definite cell outlines, in which very 
numerous mitoses may be observed, even in an adult fully- 
grown animal. At the edges of this tissue, which lies free in 
the hemoccel, cells can be seen to be detaching themselves 
which have the appearance of blood-corpuscles. This tissue 
(Pl. 12, fig. 2) is present in the same position in ‘‘ Schizopoda”’ 
and Decapoda which I have examined, and there appears to 
be little doubt that it constitutes the blood-forming organ 
of the higher Crustacea in which the blood-corpuscles are 
reproduced. 
(s) The Alimentary Canal. 
On removing the heart and the floor of the pericardium we 
find the alimentary canal with its associated glands. We 
will first shortly enumerate the various parts of the alimentary 
canal, beginning from in front backwards. 
The short dorso-ventrally directed cesophagus leads into an 
expanded stomach which is furnished with a series of com- 
plicated setose ridges. At the pyloric end of the stomach a 
short median dorsal diverticulum marks the position where 
the mid-gut or endodermal portion of the alimentary canal 
beginsand thestomodzeum ends. At the same point, but ventro- 
laterally, a great number of long, slender, liver ceca enter 
the stomach, to the number of about thirty. 
The mid-gut is continued downwards as a straight tube 
until the second abdominal segment, where a large and 
conspicuous dorsal diverticulum is givenoff. Thisdiverticulum, 
which is of a glandular nature, belongs to the mid-gut, but it 
does not mark the place where the proctodeeum begins. ‘This 
position is marked by a third diverticulum in the fifth abdo- 
