OPHIUROIDEA OF THE BAHAMA EXPEDITION. 6l 



obtuse proximal angle; the distal lobe is an elongated, nar- 

 row, oblong, blunt process, which extends out into the inter- 

 radial area. Small, rough, granule-like and verruciform ele- 

 vations occur on its proximal part, as well as on the distal. 

 The madreporic shield is larger than the others, swollen, some- 

 what triangular, without a distinct distal lobe. 



Adoral shields are very large, broad, quadrant-shaped, 

 with the straight adjacent edges broadly joined. 



The mouth-papilla?, tooth-papillae, and oral tentacle-scales 

 are all similar in form, long, acute, spiniform, and very num- 

 erous. The tooth -papillae are about ten to a jaw, in four 

 transverse rows, below the broader and flatter teeth; 

 the two upper rows consist each of a pair of papil- 

 lae, side by side; the two lowest rows, near the mar- 

 gin of the jaw, usually consist of three each, of which 

 the median ones are larger and like those above them. On 

 the middle of each side of the jaw there is a crowded diverg- 

 ent group of 14 to 17 spiniform mouth-papillae, some of 

 which arise from the ventral surface of the oral plates and 

 others from their margins; a few additional ones are situated 

 along the inner margins, up to the tooth-papillae. They are 

 mostly acute, spiniform, and minutely serrulate or rough. 



At the junction of the concave, first under arm-plate and 

 the first lateral plate there is a prominence, bordering the oral 

 tentacle-pore, and bearing a close cluster of about five or six 

 large, acute, spiniform tentacle-scales directed inward; they 

 are rather larger than the mouth-papillae, but similar in form; 

 two of these are borne on the under arm-plate and three on 

 the corner of the side arm-plate. The first arm-plate is deep- 

 ly hollowed out between the side lobes that bear spiniform 

 tentacle-scales. 



On the second and third joints there are four or five simi- 

 lar, but slightly smaller, tentacle-scales, in a conical group 

 around each pore; on five or six succeeding joints there are 

 three scales in a group, but they become thorny and more ir- 

 regular and decrease rapidly in size distally; beyond the 



