26 



ECHTSrODF.RMA. 



II. With dental papillae. 

 A. With oral papillae. 



Family 3. OPHIOCOMID.E. 



Ophiocomidse, id. t. c. p. 328. 



Spines smooth or covered with skin, disk granulated. 

 Two genera : OpJiiocoma and Ophiopsila. 



B. Without oral papillae. 



Family 4. OPHIOTHRICID^). 



Ophiothricidae, id. t. c. p. 330. 



Spines roughened or serrated, disk generally with spines or 

 spiniform rods. 



One genus : Ophiothrioc. 



Order 2. STREP TOPHITJRJV. 



Streptophiurse, Bell, P. Z. S. 1892, p. 179. 

 Ophhme (ciuct.), pars. 



Ophiuroids in which the faces of the arm -ossicles have no pits or 

 processes sufficient to prevent the ossicles being so twisted on their 

 neighbours that the arms may be coiled or rolled towards the mouth. 

 Of the covering-plates, tentacle-scales, teeth, teeth-papillae, mouth- 

 papillse, several may be absent. A single madreporite. No pedicel- 

 lariae. Arms never branch. 



Three genera : Opliioscolex, OpMobyrsa, and Opliiomyxa. 



Order 3. CLADOPHITJRM 



EuryaUdse, Gray, Syn. B. M. 42nd ed. (1840) p. 63. 

 Euryalaa, M. Tr. Syst. Ast. (1842) p. 85. 

 Asterophydees, Duj. $ Hup. Echin. (1862) p. 295. 

 Astrophytonidee, Norman, Ann. § Mag. xv. (1865) p. 104. 

 Asterophydise, Wright, Brit. Foss. Echin. Oolit. ii. (1866) p. 138. 

 Phytastra, Haeckel, Gen. Morph. ii. (1866) p. lxvii. 

 Astrophytidse, Lyman*, Chall. Rep. (1882) p. 250. 

 Cladophiur*, Bell, P. Z. S. 1892, p. 180. 



Ophiuroidea with more or less saddle-shaped faces to the arm- 



* Astrophytidse is to be found passim in the works of Mr. Lyman, but does 

 not seem to have been defined by him till 1882. 



