116 Bulletin, Vanderbilt Marine Museum, Vol. IV 



Color: In life this serpent-star is usually brown or deep gray, 

 flecked with darker tones of these colors; the arms are cross-banded 

 with brown and creamy tan alternately, the lighter bands usually 

 considerably wider than the brown markings. 



Habits: This species apparently prefers to dwell in the sheltered 

 rock crevices of the outer reefs. 



Technical description : Disk pentagonal, diameter 19 mm. ; arm 

 length 94 mm. Abactinal surface except the radial plates entirely 

 covered by small regular, rounded granules, which also cover the 

 lateral walls and interbrachial region of the actinal surface and the 

 side mouth-plates. The mouth-shields are wide heart-shaped with the 

 apex directed inward, or nearly oval. The side mouth-shields are long 

 and narrow, meeting inwardly and outwardly extending to the genital 

 slit. There are 18 mouth papillae; the outermost one is larger than 

 any of the others, with a squarish base and produced at the inner 

 distal angle into a slender, acuminate process which extends inward 

 across the margin of the second tooth to that of the third tooth. The 

 second to eighth teeth inclusive are irregular, rectangular or wedge- 

 shape; the ninth tooth is larger than the others and has a broad, 

 triangular point. The inner genital slit is short, separated from the 

 outer slit by a distance equal to one and one-half times the length of 

 the inner slit, or about equal to the outer slit which is also short and 

 does not extend to the lateral margin. The genital plates are smooth. 

 The first under arm-plate is small, triangular, wider than long, with 

 the apex directed outward and separated from the second plate by a 

 pair of submedian pores. From the second plate outward, the plates 

 are shield-shaped, about 1.4 times longer than wide, with the outer 

 margin convex, the lateral margins slightly concave ; the elongate oval 

 tentacle scale fitting close against these lateral margins. The second 

 or outer tentacle scale is not quite so long as the first and is more 

 bluntly truncated distally. The side arm-plates are nearly three times 

 as wide as the under arm-plates and have the outer margin convex 

 and especially rounded toward each end. On the eighth plate, which 

 is the first side plate entirely free, there are nine arm-spines which 

 are repeated to the sixteenth plate, beyond which there are usually 

 only eight spines, and near the arm tip these decrease to five on each 

 plate. The spines are short, conical, laterally compressed, blunt- 

 tipped, slightly decreasing in size from the ventral to dorsal size of 

 the series. There are a series of coarse, flat scales at the base of the 

 arm on the upper surface. The dorsal arm-plates are about four times 



