GASTEROPODES. 295 
diverging from it to the margin, runs down the middle of each leaf. The 
whole apparatus is retractile within the body, where the lips of a wide 
gaping cavity close over it. 
This animal is vernacularly called the Sea Lemon. From simple 
lemon-yellow it appears greatly diversified with purple patches. Of. five 
specimens taken 6th March, four were of pure lemon-yellow, and the fifth 
of faint purple, variegating a dingy yellow ground. Of other five taken 
on March 9. of a different year, some were either of plain lemon-yellow, 
or variegated with small purple patches. The principal difference among 
many appearing in nothing but the dimensions, and in the greater or 
less profusion of purple, for yellow always predominates. The finest are 
saffron-yellow. All the preceding were above middle size, or extending 
more than two inches and a half. But the full size of this animal is to 
be very seldom seen. Its torpid inactivity is surprising ; it scarcely ever 
moves, and commonly dies very soon in the first vessel to which it has 
been committed. I have never been able to preserve a specimen any 
considerable time ; and the artists have seldom procured a sufficient view 
for satisfactory representation. This seems from their real nature, but it 
may be also from the force required to detach so large a surface as the 
sole from rocks or stones. It does not appear that our specimens are 
smaller than those of foreign countries, as the Abbé Dicquemare computes 
the length of specimens on the coast of Havre at five inches. 
The reader will remember what is said of the propagation of the 
Doris verrucosa in the preceding paragraph, as I have not been so fortu- 
nate as to discover the real and undoubted distinction. 
Puate XLII. 
Fic. 4. Doris argo, back. 
5. Belly. 
6. Another larger specimen, back. 
7. Branchial apparatus. 
