22 
PEOPESSOE H. N. MOSELEY. 
laesthetes and eyes, but covered by large spines irregularly 
disposed, Moreover, thè peculiar mode of formation of thè 
sesthetes and eyes at thè margin only of thè tegmentum is 
evidence against thè homology. Were thè megalaesthetes 
homologous with thefunicles of thè spines, it would beprobable 
that inthegrowth of thè tegmentum funicle-like organscontained 
in thè margin of thè girdle would become encroached upon by 
thè tegmentum and included within it to become sesthetes, but 
such is not thè case. Eyes being absent in thè Solenogastres, 
I would suggest that thè sesthetes are organs developed origi- 
nally in connection with thè shells in thè Chitonidae, stili little 
differentiated in Chitonellus, and not homologous with thè 
spine-bearing funicles at all, which are of more ancient origin, 
occurring in Proneomenia. As a comparatively late modifica- 
tion, some of thè megalsesthetes bave been modified into eyes 
in certain genera, whilst in Chiton and other forms, thè more 
primitive coudition in which they all remain as organs of 
touch has been retained. 
The forms of thè Chitonidae which bear well-developed eyes 
appear to be mostly nou-European. It is therefore not easy 
to obtain specimens properly prepared for examining thè minute 
structure of thè retina in a satisfactory manner, but my 
father-in law, Dr. Gvvyn Jeffreys, has pointed out to me that 
Costa^ figures what are evidently eyes on one of thè inter- 
mediate shells of a very small species of Chiton, called hy him 
C. rubicundus (Ornithochiton ?), which species is common 
in Sicily. The eyes are figured as mere black dots and referred 
to as fine punctuations, but are evidently eyes. Possibly some 
interesting results might be got by examining them in thè fresh 
condition. 
In conclusiou, I would express my best thanks to Dr. 
Giinther for giving me every facility in making use of.the fine 
series of Chitonidae in thè British Museum, and allowing me 
to dissect some duplicate specimens preserved in spirits. Also 
to Professor Westwood, who supplied me with others out of 
thè Hope collection, and to Mr. W. H. Dall, who showed me 
' “ Fauna di Napoli,” ‘ Animali Molli Ciiitone,’ taf. iii, fig. 1, e. 
