ON AMPHIPORUS SPECTABILIS, 293 
at once found! that a very distinct basis-layer is described 
and figured both in Ommatoplea and Borlasia; and, moreover, 
I consider that—for the matter of homology—there is no 
need to go beyond this structure (basis-layer) in the forms 
just named and in Bipalium. Mr. Moseley thinks the basis- 
layer performs the part of a muscular tunic in the Nemer- 
teans and Planarians, but as these animals are already 
sufficiently provided with muscular layers, it can only act 
as an accessory and very efficient elastic investment (probably 
after the manner of the cuticle in the Annelida). It is often 
observed to be frilled while the subjacent circular muscular 
coat in the ENopta is straight. I have further to add that 
the late Professor Keferstein was right in saying that 
the pigment in many Planarians disappears in alcohol, and 
is much altered in others. The black pigment of the eye- 
specks, however, as Mr. Moseley observes, remains. 
The description of the primitive vascular system of 
Bipalium is novel. Mr. Moseley observes that it has the 
form of a spongy vascular tissue, and, moreover, has the 
nervous system in its interior in the form of a “ meshwork ” 
“very indistinctly differentiated histologically.” My slight 
eXamination had resulted in doubt as to the nature of this pale 
area,” for in no preparation was there any appearance to sup- 
port the “ vascular ” idea, neither could any nerve-elements 
be observed. A re-examination gives no grounds for a more 
decided expression of opinion. Further, the dissections of the 
ordinary Planarians for comparison with the Nemerteans lend 
no support to Mr. Moseley’s statement that a similar ‘ primi- 
tive vascular system ”’ exists in them near the oviduct. I still 
agree with Prof. Keferstein’s view that much more extensive 
observations both in the living and preserved Planarians are 
necessary before such can be accepted as a ‘‘ primitive 
vascular system.” Finally, nothing has been seen to sub- 
stantiate the notion that the ganglia of the Planarians lie 
within a .‘ primitive vascular sinus.” Indeed, 1 am bound 
to say that such a view is wholly opposed to my experience 
both in the Planarians and Nemerteans.* In not a few of the 
latter two muscular layers intervene between the vascular 
and the central nervous systems; and, ifin either groupa 
pale area surrounds the ganglia, it is widely different from 
‘“ spongy vascular tissue.” The nerve-cells of the Planarian 
ganglia are exceptionally large and distinct, and they are 
well represented by Mr. Moseley. 
1 «Trans. R. S. Edin.,’ vol xxv, p. 308, pl. iv. 
2 Op. cit., Ray Soc., p. 143. 3 Ibid., p. 141. 
4 The condition of the cephalic sacs and the pre-ganglionic meshes at the 
proboscidian canal in the Lineide do not affect this opinion. 
