OPHIURANS OF UNITED STATES NATIONAL MUSEUM. 87 



its distal side is rounded. Tlie adoral plates are well developed, fairly large, very 

 much widened inwardly and narrower outwardly. The oral plates, wliich are 

 triangular, are ratlier small. AU these plates are covered with fine granulations. 

 The oral papilla? amount to three or four on each side; they are rather strong and 

 conical and their end is sometimes pointed, sometimes blunt. The dental papUla, 

 wlxich is single and odd, is larger than the neighboring oval papUlse. 



Tlie upper bracliial plates of middling size are triangular, with a fairly open 

 proximal angle, and slightly corrugated diverging lateral sides, and a wide and 

 convex distal side. These plates are almost as wide as long, and they are separated 

 from the bases of the arms by a fairly narrow interval. 



The under braclual ])lates are remarkably short and wide, as pointed out by 

 Verrill, and they are broadly separated by the lateral ])lates. Tlie fii"st one is wider 

 than long, quadrangular, with a rounded and convex distal side, a concave proximal 

 side, and two diverging lateral sides. The following ones are extremely wide, at 

 least four times wider than long and triangular, with a very obtuse proximal angle 

 limited by narrow sides, winch meet the distal edge by faiiiy acute angles; the said 

 distal edge is extremely wide and often excavated in its middle. At a certain 

 distance from the tUsk the plates become narrower and comparatively a little 

 longer; they are then pentagonal, with two diverging lateral sides, wluch are 

 excavated by the corresponding tentacular scale, and a convex distal side. 



The lateral plates carry eight or nine spines. The ventral spines are rather 

 tliick and obtuse at their ends. The length of the first one exceeds the article, and 

 increases on the following spines up to the last dorsal ones, which are equal to two 

 and a half or tliree articles ; these are pointed and comparatively thinner than the 

 ventral spines. The surface of all these spines is rough or even covered with small, 

 conical, and pointed asperities, wliich are put very close together. The two lateral 

 rows of si)ines are not approximated dorsally. 



The tentacular scale, which is always single, is small and short, conical or 

 lanceolated; its surface is rough or it is even provided on its sides and at its end 

 with extremely small spinules. 



OPHIACANTHA LINEATA Koehler. 

 Ophiacantha lineala KtEHLER (09), p. 187, pi. 25, figs. 6-8. 



Albatross station 2415. Apr. 1, 1885. Lai. 30° 44' N.; long. 79° 26' W.; 

 440 fathoms; co. crs. s. sh. for.; temp. 45.6° F. One specimen. 



Albatross station 2667. May 5, 1886. Lat. 30° 53' N.; long. 79° 42' .30" W.; 

 273 fathoms; gy. s. bk. sp.; temp. 48.7° F. One specimen. 



Both specimens are small and the diameter of the disk does not exceed 5 mm. ; 

 moreover, they are in a very bad state, the arms are broken at their base or preserved 

 only for a very short length; besides, some rubbing has taken place, wliich caused 

 almost aU the stumps of the upper face of the disk to be torn. Nevertheless, I 

 found again the characters which I originally ascribed to 0. lineata, and I tliink 

 the specimens may be referred to that species. 



A very young example, the diameter of the disk of wliich did not exceed 2 mm., 

 is associated with that from station 2415, and undoubtedly also belongs to 0. lineata. 

 6061°— Bull. 84—14—7 



