4 
OtEnekal description 
which is next to the centre; its BACK (jyostica), that which 
is next to the margin ; its RIGHT and LEFT sides (latus 
dextrum, 1. sinistrum), those which depend upon these 
indications. Each tentacle has a foot {radix) and a tip 
{apex). 
5. The Mouth (Os). 
The entrance to the stomach is placed, as has been stated 
above, in the centre of the disk. It is surrounded by a 
generally thickened lip [labium), which is sometimes 
elevated on a cone [colliculus), and sometimes level. The 
LIP may be smooth [Iceve), or FURROWED [sulcatum) ; at 
each of two opposite points, — the mouth-angles [gonidia), 
— there are placed two tubercles [lentigines) , between which 
opens an imperfect tube or groove formed by the approxi- 
mation of two cartilaginous bands : these grooves, one at 
each mouth-angle, may be termed gonidial grooves 
[canales gonidiales). Their function appears to be that of 
oviducts. (In Actinoloba, there is but a single mouth- 
angle, and a single groove).* From the lip descends 
into the cavity of the body a membranous veil, much 
gathered into folds, but free at the lower edge, like a sack 
without a bottom ; this is the STOMACH [stomachus) , of 
which the portion immediately below the lip may be 
conveniently termed the throat [gula). 
6. The Cavity [Venter). 
The whole of the region included between the walls of 
the column and the stomaeh-wall, and between the free 
edge of the stomaeh and the base, may be indicated by 
this term. It is divided into imperfeet ehambers by 
* In Actinopsis, a singular form recently described by Messrs. Danielssen 
and Keren from the Norwegian coast, the gonidial tubercles are prolonged 
into a pair of long and rigid semi-cylinders, the sides of which are bent 
downwards, and the tips of w’hich are cleft. 
