124 Bulletin, Vanderbilt Marine Museum, Vol. IV 



the inner lateral short, somewhat recurved, meeting in an angle in 

 their middle line. The side mouth-shields are as wide as the mouth- 

 shield, the margins are very little curved and produced without to a 

 point. The under arm-plates are wider than long, 1.6 :1, a trifle 

 narrower within than without, squarish with rounded corners ; the 

 outer and inner sides almost straight ; the lateral margins slightly 

 concave. The first under arm-plate is much wider than long, nearly 

 oval, with an inward projection filling the end of the mouth-slit. 

 Toward the outer end of the arm these plates are distinctly wider 

 and more convex on the outer than on the inner margin, bounded 

 within by a nearly straight median lateral and two oblique inner 

 laterals; the lateral concave and the outer margin shallowly convex. 

 Tentacle scales two, together forming almost an oval. The side arm- 

 plates are decidedly arched extending on the surface for a distance 

 fully equal to the width of the ventral plate. These side plates also 

 arch over on the dorsal surface of the arm for a considerable space. 

 The dorsal plates are for the first seven or eight wider than long, 

 margined within and without by straight lines, and laterally by short, 

 convex lines; beyond the eighth, these plates become hexagonal, still 

 farther towards the tip they become fan-shaped. The supplementary 

 pieces are slender, triangular, with the apex directed downward. 

 Arm-spines, near the base of the arm, six, farther out five short, 

 rounded, blunt, scarcely tapering. 



References: Ophiolepis elegans Lutken, C. F., Vid. Selsk. Skrifter 

 V. Raekke, Naturg. og Math. Afh. V, Bind, V, p. 207, 1861.— 

 Lyman, Th., Mem. Mus. Comp. Zool., vol. I, art. 1, p. 58, pi. 2, 

 fig. 5, (colored), 1865.— H. L. Clark, ibid, XXXV, p. 342, 1915. 



ECHINOIDEA. 



Order: CIDAROIDA. 



Family: CIDARIDAE. 



Genus : CIDAKIS Klein, s.s. 

 Cidaris aflinis (Philippi). 



Plates 77, 78 and 79. 



Type: Philippi 's type was taken in the Bay of Naples, in 50-100 

 fms. 



Distribution : This species is found in both the Mediterranean 

 region and the "West Indian region. Bathymetric occurrence: 3 to 

 426 fms. 



