334 MANUAL OF NATURAL HISTORY. 



2. FAMILY. Gorgon-Heads (Euryalidse). Body or- 

 bicular, depressed, covered with a leathery 

 skin, strengthened behind by five pairs of 

 radiating ribs ; arms compressed, rounded or 

 square, with a series of pores on each side, 

 and usually repeatedly branching; mouth 

 inferior, central. 



VI. ORDER PINNATE-ARMED STARFISHES 

 (Piniiigrada). 



Rays furnished with pinnae, having the skin deve- 

 loped on their sides, so as to be the principal organs 

 of progression through the water ; generative sys- 

 tem spread over tegumentary covering of body and 

 arms ; free, or attached to foreign bodies by a peduncle. 



I. SUB-ORDER. FREE-CRINOIDEANS (Liberida). 



Either permanently unattached or become so in 

 their mature state ; some furnished with a tapering 

 column, enabling the animal to attach or detach 

 itself at will. 



1. FAMILY. Feather -Stars (Antedonidse). Rays 



five, subdivided and pinnate, resembling fea- 

 thers ; free when adult, young fixed and 

 stalked. (Comatula, Lam.) 



II. SUB-ORDER. FIXED-CRINOIDEANS (Oionacineta). 



Fixed to extraneous objects, usually by a jointed, 

 flexible column attached to the dorsal surfaca 



2. FAMILY. Pedunculated Lily -stars (Pentacrini- 



tidse). Rays with numerous jointed lateral 

 appendages ; peduncle five-sided, jointed, with 



