56 
PROFESSOR H. N. MOSELEY. 
laesthetes and eves, but covered by large spines irregularly 
disposed. Moreover, the peculiar mode of formation of the 
aesthetes and eyes at the margin only of the tegmentum is 
evidence against the homology. Were the megalaesthetes 
homologous with the funicles of the spines, it would be probable 
that in the growth of the tegmentum funicle-like organs contained 
in the margin of the girdle would become encroached upon by 
the tegmentum and included within it to become aesthetes, but 
such is not the case. Eyes being absent in the Solenogastres, 
I would suggest that the aesthetes are organs developed origi- 
nally in connection with the shells in the Chitonidae, still little 
differentiated in Chitonellus, and not homologous with the 
spine-bearing funicles at all, which are of more ancient origin , 
occurring in Proneomenia. As a comparatively late modifica- 
tion, some of the megalaesthetes have been modified into eyes 
in certain genera, whilst in Chiton and other forms, the more 
primitive condition in which they all remain as organs of 
touch has been retained. 
The forms of the Chitonidae which bear well-developed eyes 
appear to be mostly non-European. It is therefore not easy 
to obtain specimens properly prepared for examining the minute 
structure of the retina in a satisfactory manner, but my 
father-in-law, Dr. Gwyn Jeffreys, has pointed out to me that 
Costa 1 figures what are evidently eyes on one of the inter- 
mediate shells of a very small species of Chiton, called by 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 the fresh 
condition. 
In conclusion, I would express my best thanks to Dr. 
Gunther for giving me every facility in making use of the fine 
series of Chitonidae in the British Museum, and allowing me 
to dissect some duplicate specimens preserved in spirits. Also 
to Professor Westwood, who supplied me with others out of 
the Hope collection, and to Mr. W. H. Dali, who showed me 
1 “ Fauna di Napoli,” ‘ Animali Molli Chitone,’ taf. iii, fig. 1, e. 
