DESCRIPTION OF NEW SPECIES, 



OPHIOMAZA.* Gen. nov. 



Teeth. Tooth-papillEe numerous, and arranged in a close vertical 

 oval, as in Oplmthiix. No moutli-papilla\ Disk below naked, but 

 covered above with large, swollen radial-shields and plates. Ann- 

 spines stout, nearly smooth, as in Ophiocoma. 



This curious genus has the dentition of Ophiothix, the disk of Ophio- 

 cnemis, and the arms of Ophiocoma. 



Ophiomaza cacaotica. Sp. nov. 



Plate I., fig. 15. 



Special 3farks. — Five, sometimes six arm-spines, the two or three 

 upper ones considerably largest. No tentacle-scale. Interbrachial 

 plates on back of disk elongated and irregularly broken. 



Description of a Specimen. — Diameter of disk, 11""» ; from outer side 

 of mouth-shield to outer corner of opposite mouth-slit, 4.2°"°- ; distance 

 from outer side of mouth-shield to inner points of tooth-papilla?, com- 

 pared to that between outer corners of mouth-slits, 2.5 : 2. Width of 

 arm, 2°""- ; length of arm about 30"""- ; tooth-papillae small and crowded, 

 about 26 to each angle of the mouth ; four strong, square-edged teeth. 

 Under arm-plates, beyond edge of disk, broader than long ; their lat- 

 erals and inner side slightly re-cnteringly curved ; outer side slightly 

 curved; length to breadth (6th plate), 9: 1.2. Within the disk there 

 are six plates, of which the one next the mouth-slit is small and oval ; 

 those outside of it grow gradually In-oader and are shaped like those 

 beyond the disk ; side arm-plates stout, but not much projecting ; upper 

 arm-plates broader than long, somewhat irregular, broader without 

 than within, outer side curved ; length to breadth (8th plate), .9 : 1.6. 

 The first two or three plates are narrow and wedge-shaped and fit in a 

 notch in the disk ; beyond the margin they grow wider, and have their 



* "Orfm. serpent ; fia^a, a oake. 

 NO. VI. 2 



