2 
2 General Notes. [ March, 
Fig. 2, B represents an optical section of the head end of one 
like that shown at D in profile, and 
shows the oblong attached internal 
Z3 — bodies in an excentric position with 
= = = reference to the enveloping mem- 
B C brane. Excessively minute round 
granules were found mixed in great 
ES D oe abundance with the tailed forms. 
These are veritable psorosperms 
Fic, 2.—Psorosperms. and are almost identical in form with 
those found by Müller in 1841, in European freshwater fishes. 
The above description is not different in any essential particular, . 
from that given by Müller, and I only offer this account in order 
that it may induce others to look for similar parasites in other 
common vertebrates. Cobbold states that they are harmless if 
eaten with the flesh which contains them, stating that in eating of 
the heart of a healthy ox, which had furnished part of two meals, 
he himself must have consumed at least 18,000 of these parasites. 
They are supposed to be an embryonic stage of development of 
the Gregarines. 
Psorosperms, have not, as far as I am aware, been recorded as 
being found in Aphredoderus, which is a characteristically American 
fish. There must have been half a million of these embryonic 
gregarines in the individual fish which I examined.—- Fon « 
Ryder. 
small simple eyes on the front of the head. As described by A. 
Milne-Edwards and Owen, the optic nerves to these eyes are very 
Jong and slender. Those distributed to ‘the larger compound 
eyes are very long, and close to each eye subdivide into an irreg- 
ular plexus of fine nerves, a branch being, as we have found, dis- 
tributed to each facet composing the,compound eye. The struc- 
ture of the eye is very unlike that of any other Arthropod eye. 
, the cornea externally being structure- 
less, simply laminated like the rest of the integument. In the 
through the smooth convex translucent cornea, give the appear- 
ance of a facetted surface to the external eye. J 
