58 
blood-corpuscles than almost any other part of the intestinal folds (fig. 
32). Here again the layer intervening between the blood and the 
seawater (which may enter by way of the anal opening) is only 
one cell thick. It was above noticed how in all probability the 
blood from the ventral sinus finds its way towards these folds, but 
here especially a great deal remains to be done by careful invest-: 
igation of further specimens. One certain result of the present 
investigation is that a branchial apparatus comparable to that of 
Neomenia and Chaetoderma is absent in Proneomenia. 
The number of blood-corpuscles of comparatively large size ap- 
pears to be very considerable in Proneomenia. The shape by 
which they are generally distinguished, after having passed through 
the different stages of conservation and being finally preserved in 
canada-balsam is rather noteworthy. The cell appears oi an elliptical 
form, the long axis measuring 0.022 mm., the short one 0.012 mm. 
(ig. 27). The nucleus is closely applied to the wall and stains 
very well. The protoplasm appears to contract into a very quaint 
fusiform-shaped body, always situated in the long axis and faintly 
rosecoloured after application of picrocarmine. ‚lt touches the cell- 
wall at the extremities and is represented as seen from above in fig. 27. 
Nearly all the blood-corpuscles correspond in this respect and an 
examination of fresh specimens will alone furnish evidence whether 
really this curious shape is due to an abnormal contraction after 
preservation. The presence of a large number of apparently more 
spherical blood-corpuscles of the ordinary shape must however not 
be passed over in silence. The colour of the blood-corpuscles after 
preservation leads me to the assumption, on comparison with simi- 
larly preserved corpuscules in other classes of invertebrates which 
have been proved to contain haemoglobin, that it is far from im- 
probable, that a spectroscopice examination of them in the fresh 
state will prove them also to contain haemoglobin. Kor£n’s and 
DanıEussen’s statement (16) that the branchiae are bright red, 
the foot and buccal massred, render thiseven more probable, after 
what we have noticed about the eirculation in these organs. 
