LECTURE X. 
149 
ed ; while the whole surface of the body is mark- 
ed into numerous, slightly-prominent, reticular 
spaces of a triangular figure. It is a native of the 
Indian seas. 
The Ast. Gigas ^ is of similar size and colour, 
and is all over roughened by small pointed pro- 
tuberances, which also verge the margins of the 
rays : it is a native of the Atlantic, and is well 
figured in the magnificent work of Seba. 
Of the British species the A. papposa or com- 
mon twelve-rayed Star-fish is a good example. Its 
colour is a dark yellowish red, and its surface 
roughened by very numerous small protuberances. 
Its usual number of rays or limits is twelve, but 
it varies, from ten or eleven, to thirteen or even 
fifteen. 
The most curious of the whole tribe is the A, 
Caput Medusae, of Linnaeus, or Medusa’s Head 
Star-Fish, It grows to a large extent, measuring 
more than two feet in diameter when the limbs 
are fully extended. This very extraordinary ani- 
mal is first divided into five equidistant, jointed 
processes, each of which is soon subdivided into 
* A. Gigas. r Mus. Tessin, pi. 9, 
