236 ANTHOZOA HELIANTHOIDA. 



mouth was of course prevented, yet instead of emaciating and dying 

 of an atrophy, the animal had availed itself of what undoubtedly 

 had been a very untoward accident, to increase its enjoyments and 

 its chances of double fare. A new mouth, furnished with two rows 

 of numerous tentacula, was opened up on what had been the base, 

 and led to the under stomach : the individual had indeed become 

 a sort of Siamese twin, but with greater intimacy and extent in its 

 unions ! 



The existence of nerves in the structure of the Actiniae is still 

 doubtful. Spix tells us, that he detected near the base and centre 

 of the body some small nodules or ganglions placed in pairs, from 

 which filaments emanate towards the circumference, constituting, as 

 he believes, their nervous system. Blainville asserts, however, that 

 in numerous dissections made with every possible care, he could see 

 nothing like what Spix has described and figured ; and the only 

 part that he can regard as nervous, is a sort of grey pulpy cord in 

 the margin of the labial rim. Delle Chiaje and Mr. Teale agree 

 with Blainville.* Be the fact as it may, we know that every part 

 of the body is very sensible to external irritations : no point of the 

 skin, the tentacula, nor the membrane of the stomach can be 

 touched, but immediately the creature evidences its sense of the 

 injury by contractions and other motions of the part. They are 

 said also to be very sensible of atmospherical changes : they shrink 

 under a glare of light ;f but in a calm and unclouded sky expand 

 and disclose every beauty, while they remain contracted and veiled 

 in cloudy or stormy weather. Dicquemare has even found, from 

 several experiments, that they foretell changes in the weather as 

 certainly as the barometer. When they remain naturally closed, 



* But Dr. Grant says "The nervous system has been long known in the 

 Actinia." " Nervous filaments surround the muscular foot of the Actinia, beneath 

 the stomach, and present minute ganglia in their course, from which nerves pass out 

 to the circumference, and to the muscular folds which here possess great power of 

 contraction. The same system probably exists in many other closely allied forms of 

 polypi." Outlines of Comp. Anat. p. 182. 



t It has been suggested that their perception of light may be communicated 

 through the tentacula, on the tips of which, Bosc assures us, there is a black point or 

 eye. Vers, vol. ii. p. 247. This black point, as well as the other parts of Bosc's 

 description of the tentacula, is wholly imaginary ; nor is there a necessity for an eye 

 to explain the phenomena, for there can be " little doubt that a diffused sensibility to 

 light and sound exists in animals which present no special organs of vision or hear- 

 ing." Brit, and Foreign Med. Rev. v. p. 491. I have already mentioned that the 

 coloured spot on each side of the mouth, in the commissure of the stomachical mem- 

 brane, is a visual organ in the opinion of Mr. Cocks. 



