LECTURE X. 
147 
in size, though they frequently produce a numer- 
ous offspring, being of a very prolific nature, and 
viviparous. The young are produced of various 
sizes, from that of a pin’s head to that of half an 
inch in diameter, and to the number of five, ten, or 
more at a birth. As these animals are allied to the 
Polype tribe in some degree, they partake of their 
qualities, and will reproduce many of their organs, 
when either purposely or accidentally mutilated. 
The minuter genera of the Mollusca it would 
be tedious and uninteresting to particularize in 
the course of a lecture, but the larger and more 
remarkable ones justly demand our attention. Of 
these the genus Asterias or Star-Fish is one of the 
chief : it is rather of a coriaceous or crustaceou 
nature than of that soft cast so common to many 
other of the Mollusca. The generic character 
consists in having a depressed body, covered by a 
coriaceous or tough integument, roughened by 
very numerous small processes or tentacula. The 
mouth is central, and situated beneath. By far 
the greater number of the Sea-Stars or Asterias are 
of a stellated or radiated shape ; several lengthen- 
ed arms or limbs proceeding from the common 
body or central part, so that the animal represents 
