276 NEW STARFISHES AND OPHIURANS—VERRILL. vol. xvii. 



The integiimeut between the spiuules is thick, smooth, firm, and 

 everywhere perforated by numerous very small, round pores. 



In each interradial region there is a narrow, radiating groove, lined 

 with thick naked integument, destitute both of spinules and pores, but 

 showing a wrinkled surface. These grooves commence at about one- 

 fourth the distance from the dorsal center to the margin. In some 

 cases there is only a small slit-like opening in the upper end of the 

 groove, communicating with the space beneath the dorsal membrane, 

 but in some of the interradii the slit is much larger and longer, reach- 

 ing nearly or quite to the margin, and communicates with a large 

 marsupial pouch, containing well-formed young, some of which were in 

 the act of escaping when preserved. Apparently the slit-like openings 

 are formed, or at least much enlarged, when the young are ready to 

 come forth, and after their birth the edges of the slits may become 

 again united. 



The dorsal spines or pseudopaxillre beneath the integument are 

 large, stout, rather long, and surmounted with a large divergent group 

 of long, slender spinules. In the interradial region, within the mar- 

 supial pouch, there is a group of several lobed or branched papulte at 

 the base of each paxilliform spine. The large spines situated along 

 each side, within these cavities, have rudimentary spinules at the sum- 

 mit, which do not reach the outer membrane so that they stand free 

 within the cavity, thus leaving the membrane unsupported along the 

 slits. On the ventral side the rays are nearly flat, and the disk around 

 the mouth is deeply concave. 



Each ray is broadest at the margin of the disk. The transverse 

 combs are numerous and covered with a thick, firm skin, which entirely 

 conceals the si^ines in alcoholic specimens. On the broadest part of 

 the ray, opposite the margin of the disk, there are mostly four, rarely 

 five, spines of moderate length in each comb; of these the one next the 

 groove is somewhat shorter than the two or three which succeed it, 

 while the outermost is still shorter and directed more outward, so that 

 the group has a somewhat rounded, but not very elevated, scolloped 

 margin, tlie membrane receding somewhat between the points of the 

 spines. The spines, when exj)osed, are rather slender, flattened, rough, 

 and truncate at the flat tip; beyond the outer spine the web rapidly 

 becomes less elevated and each comb lies somewhat obliquely over the 

 one next beyond it, and becomes only a slightly elevated broad fold 

 before reaching the margin. These folds entirely conceal the trans- 

 verse, ventral sjiines, which extend to the margin of the ray, but pro- 

 ject beyond it very little, if at all, so that the margin is only crenulate 

 or separated into small blunt lobes, separated by slight notches. 



Between the outer ends of the combs of webbed spines there is a 

 small, oval pore, which is sometimes covered by an oval operculum, 

 but in some cases it gives exit to a group of two or three short, blunt 

 papuliform organs. 



