44 



situated interiorly : the exterior being occupied by the poly- 

 pes and the fleshy crust. The general appearance of the order 

 varies a great deal in the different families, each being dis- 

 similar from the others ; one is palmate and arborescent, 

 another crustaceous and lobulated, and another plumous and 

 linear elongated; but they may all be readily known by having 

 eight-rayed starred depressions distributed over the surface. 

 The character of the order is : Polypes compound, mouth 

 encircled with eight fringed tentacula ; stomach membranous 

 with dependent vasculiform appendages at it s*base ; anus none • 

 intestine none ; reproductive gemmules produced interiorly. 

 Polypidom, when existing, internal, horny or calcareous, free 

 or rooted ; polype mass arborescent, lobed or plumous j external 

 cm '.st fleshy, marked with star-shaped depressions of eight rays, 

 for the polypes. All the species are compound, or composed 

 of an aggregated series of polypes. The British species are 

 distributed over the three families of Gorgoniad&, Alcyonidce 

 and Pennatulidaii of the last of which no species has yet 

 been found in the Cornish seas; though Bellamy in his 

 Natural History of South Devon mentions that Pennatula 

 phosphorea has been found in Devon by Turton. 



The Cornish species of the order, therefore divide them- 

 selves into two very natural groups; the Gorgoniadce, being 

 arborescent with an internal horny axis ; the Alcyonidce, en- 

 crusting or lobulated and destitute of an axis. 



The form of the polype is common to the whole order 

 and is the part by which it is characterized. In its ex- 

 panded state it is a transparent truncated cone ; having its 

 base towards the polypidom, and the truncated extremity 

 raised and surrounded by eight fringed tentacula. The sides 

 being transparent, allow all the internal organs to be seen, 

 and this transparent membrane is composed of two layers, 

 one of which is continuous with the external investing mem- 

 brane of the crusts and the other is continuous from the 

 polypes to the cells and tubes, forming their internal serous 

 lining. In the centre of the circle formed by the tentacula is 

 the mouth, which opens by a short and narrow passage into 

 the stomach. The stomach is membranous and hung sus- 

 pended in the upper and central portion of the transparent 

 cavity, but separated from the sides by an intervening space 

 which is divided into compartments by eight transparent 

 longitudinal septa. These septa appear to be formed of folds 

 of the internal membrane of tfie polype and are attached to 

 the outer surface of the stomach ; but as they are longer than 

 that organ, a portion of their internal edge is unattached and 

 hangs loosely in the cavity beneath. At the base of the 

 stomach is a minute orifice which appears to be guarded 

 by a circular muscle, which opens into the abdominal cavity 



