142 TECTIBRANCHIATA.—APLYSIADA. 
nomenon in a West Indian species, and Mr. Patter- 
son thus speaks of it in our native species, 4. hy- 
brida. “The first which our dredge brought up 
was placed on one of the rowing benches of the 
boat, and in a very short time emitted a rich 
purplish fluid, so copiously, that it ran along the 
board. Being transferred to a phial of sea-water, 
the purple dye was still given off in such abun- 
dance that the creature soon became indiscernible. 
It was not until the water was again changed that 
we had the opportunity of observing the ease and 
grace with which it moved about, elevating and 
depressing its mantle, altering the outline of its 
body, and extending and retracting its tentacula so 
incessantly, that an artist would have found a dif- 
ficulty in catching its characteristic figure.”* This 
fluid is said by Professor Goodsir to be secreted by 
the edge and internal surface. The secreting sur- 
face of the mantle consists of an arrangement of 
special nucleated cells, which are distended with a 
dark purple matter.T 
Besides the purple secretion, the Sea-hares 
occasionally discharge, from an orifice situated 
behind the oviduct, a milky fluid highly acrid, and 
probably containing stinging thread capsules similar 
to those already described in Holis. The Sea- 
hares have in all ages sustained the imputation of 
being highly offensive and injurious to man, and 
though in modern works it has been the custom to 
ridicule the charge, there is reason to think it may 
not be altogether groundless. Barbut declares that 
a sailor, in the Mediterranean, happening to take 
hold of an Aplysia, it gave him such instantaneous 
and excruciating pain, as to cause inflammation and 
* Zool. for Schools, i.179. + Anat. and Pathol, Obs. 23. 
