480 PHILOSOPHY OF ZOOLOGY. 



glandular organ, the use of which is unknown, but which 

 some suppose to be employed to secrete an acrid liquor re- 

 garded as venomous. 



It is obvious from this structure, that the seminal fluid 

 and eggs must come in contact in the common canal, and 

 at the single orifice, provided they are both ejected at the 

 same time. From the orifice to the right fore-feeler there 

 is a sulcus, leading to the pore containing the retractile pe- 

 nis. This organ, like those of the other mollusca, is solid, 

 It terminates in a small filament. The external groove is 

 the only connection between it and the other sexual organs. 



There is a peculiar secretion of a purple fluid, which 

 here deserves to be recorded. It issues from a spongy 

 texture, underneath the free side of the dorsal plate. Con- 

 nected with this cellular reservoir is a glandular body of a 

 considerable size, which is supposed to secrete the coloured 

 fluid. This gland is supplied by a large branch of the 

 glandular aorta, and gives out two very large veins to the 

 left vena cava. 



The purple fluid itself has never been carefully investi- 

 gated. It is not altered by the air after drying, nor is its 

 colour destroyed by acids or alkalies, although the tint is a 

 little changed, and rendered less pure. Both these re- 

 agents precipitate white flakes from the fluid. 



This liquor is poured out by the animal when in danger 

 or constrained, and colours the water for several yards 

 around. It ejects it readily when put in fresh water ; and, 

 when entangled in a net, several yards of it in the neigh- 

 bourhood are sometimes stained, greatly to the amazement 

 of the unsuspecting fishermen. 



The Aplysia has been long known in the records of su- 

 perstition under the name of the Sea Hare. Its flesh, and 

 the inky fluid it pours out, have been regarded as delete- 

 rious to the human frame. Even to touch it was supposed 



