MUSEUM OF COMPARATIVE ZOOLOGY. 233 



Ophiomaza cacaotica Lym., and Ophiocnemis obscura L.JN., which 

 have been considered as perhaps the same, arc. on comparing the originals, 

 quite different. The two specimens of 0. obscura at Stockholm have the 

 interbrachial spaces on the back of the disk, covered by four or five very 

 irregular radiating lines of elongated scales, covered by a thick skin so as to 

 obliterate their outlines ; in the centre, a great number of similar but rounded 

 scales. The upper arm-plates are as wide at the base of the arm as beyond, 

 ami there is scarcely any notch in the margin above the arm. The specimen 

 at Copenhagen, which Dr. Liitken took to be 0. obscura (Addit. ad Hist. 

 Oph. 40), is really 0. cacaotica, which has in each interbrachial space above, 

 only one. or at most two, radiating rows of plates, which are naked, swollen, 

 and clearly denned. Furthermore, however, there is in the Museum Godef- 

 froy ( Xi>. 6258) a dried specimen of Ophiomaza, considerably like 0. cacaotica, 

 but with a fine scaling i nhricated on the interbrachial spaces below. It may 

 he this scaling always exists, but is usually hidden by the extremely thick 

 skin. As to Ophiomaza being separated generieally from Ophiocnemis by the 

 absence of granulation on the disk, I can only say that the same distinction 

 is allowed to separate Ophiarthrum from Ophiocoma. 



Ophiocnemis marmorata, see Ophiothrix clypeata. 



Ophiothrix comata Mi'i.r.. & Tk. has not been since found and 

 is generally ignored. The originals in the Vienna Museum are dry and 

 nearly ruined by time. It is therefore wed to note that the species belongs 

 to the division of the u'<'iius which ha.- long needle-like spine-', a thin disk, 

 and slender rounded arms. 0. Suensonii is its type, and 0. comata resembles 

 it considerably. The sketches (Plate IV.. Figs. 27, 28) show that the shapes 

 both of upper and under arm-plates are different; and whereas 0. Suensonii 

 has a purple arm-stripe above and below, 0. comata has, along the upper 

 arm, a central white stripe bordered by a purple line on each side, and no 

 Stripe at all below. 



Ophiothrix fumaria Mull. & Tk. (Plate IV.. Figs. 33-3(1). Originals at 

 the Garden of Plants; dry. and in bad condition. Diameter of disk 9.5 mm. 

 Length of arm 42 nun. Disk-scales conspicuous and bearing thorny cylinders 

 (Fig. 3ii), which are scattered over the disk, as shown in Fig. 33. Arm- 

 spines seven, rounded, the second and third longest, "2..") mm, and slightly 

 cluli-ended. They are opaque and feebly thorny (Fig. 3.~>). Under arm- 

 plates wider than long, of ;ui angular oval shape (I'd-. 34). It resembles <>. 

 aspidota, but has coarser disk-stumps ami much shorter arms. I have an 

 Ophiuran from Banka Strait which resembles it closely but has narrower 

 under arm-plates. 



Ophiothrix ciliaris Mull. & Tr. (Plate IV.. Figs. 29-32). Origi- 

 nals at the Garden of Plant-: belonging with 0. fumaria, and in similar 

 condition. Diameter of disk 5 mm. ; length of arm 3.) mm. Seven or eight 



