218 ME. W. PEECT SLADEN OK THE 



margin of the plate, ranged serially above and behind the anterior 

 pair of spines just mentioned, and interlocking with the cor- 

 responding spines of the neighbouring mouth-angle. 



Actino-lateral spines numerous and very closely placed, the 

 longest spine far out upon the ray, — a much greater number 

 being included within the disk-angle than usual. About 40 

 spines stand on each side of a ray, the 20th or 21st from the 

 mouth being longest. The spines within the disk are compara- 

 tively short and uniform in length, and do not quite meet in the 

 median interbrachial line ; muscular fibres, however, may 

 frequently be seen underlying the outer tissue, passing from the 

 tips of the lateral spines to the corresponding ones of the neigh- 

 bouring ray. In the immediate arm-angle, however, the spines 

 are longer than the space between the angle and the furrow; 

 so that a considerable overlap takes place, and a consequent 

 puckering and deformity of the tissue ensues, which appears to 

 develop frequently into an unsightly excrescence. The spinelets 

 succeeding to the long ones taper very rapidly in size towards 

 the extremity of the ray. 



Colour, in alcohol, brownish white or grey. 



Station 158. Lat. 50° 1' S., long. 123° 4' E. Depth 1800 

 fms. ; bottom temperature 0°"3 C. ; Gloligerina- ooze. 



Htmenasteb, echintjlatus, n. sp. 



Marginal contour pentagonoid ; interradial angles moderately 

 indented, the lesser radius being in the proportion of 727 per 

 cent. ; B = 22 millim., r = 16 millim. The radii are sharply tapered 

 at the extremity, although when seen from above the angles of 

 the pentagon have the appearance of being well-rounded, in con- 

 sequence of the outspreading and graceful curve of the marginal 

 fringe ; this is nipped together laterally at the extreme tip, and 

 a slight upward continuation of the furrow is produced thereby. 

 Eorm depressed, dorsal area slightly conoid, interradial spaces 

 considerably sunken. 



Supradorsal membrane thick and opaque, with very robust 

 broad muscular fibrous bands, closely but irregularly reticulated, 

 the interspaces being small, usually oval, and each occupied by a 

 single spiraculum. Paxillae rather widely spaced, the tips of 

 the spinelets forming prominent little conical peaks or elevations 

 of the membrane, which on certain parts of the area conform 

 themselves to a regular definite order of arrangement. A curved 



