NO. 1807. A NEW GENUS OF STARFISHES— FISHER. 661 



arranged along median radial areas but in regular oblique and cross- 

 wise series on dorsolateral portions of ray; tabula of plates surmounted 

 by a dense brush of very many extremely delicate sharp glassy hair- 

 hke spinelets. Papulae in four or five areas about each abactinal 

 plate; one or two papulae to an area. Adambulacral plates squarish, 

 with three or four furrow spinelets basally webbed and very numer- 

 ous, smaller, actinal spinelets. Actinal interradial areas small, the 

 plates in three to five rows, with a central convexity or tabulum, and 

 strongly imbricated in chevrons. Superambulacral plates absent; 

 anus present; gonads interradial; tube feet in two series with sucking 

 disks, without deposits; ampullae incipiently bilobed; interbrachial 

 septa calcified. 



HYALINOTHRIX MILLESPINA, new species. 



Diagnosis. — Rays 5; R = 45 to 50 mm., r = 10 to 11 mm.; R=4 to 

 5 r; breadth of ray at widest part 13 mm. Disk small; rays well 

 arched abactinally, subplane actinally, bluntly pointed and slightly 

 constricted at base. Abactinal plates four or five lobed, with low 

 tabula bearing 75 to 100 very slender clear spicules, wliich give the 

 appearance of the pile or nap of plush; papulae one or two to an area, 

 usually four areas about each plate; marginal plates only slightly 

 larger than adjacent abactinals; proximally three or four regular 

 series of actinal intermediate plates, distally only one. Adambu- 

 lacral plates with three or four furrow spinelets in a straight series, 

 and on actinal surface a dense squarish or roundish paxilliform group 

 of numerous slender spinelets. 



Description. — The skeleton is in the form of irregularly four or five 

 lobed tabulate plates, which overlap by the lobes, leaving irregular 

 papular areas smaller than the plates and containing usually single 

 papulae. On the midradial area and center of disk the plates are not 

 regularly arranged, but on the sides of the rays they are in pretty 

 regular quincunx as far as the superomarginal series, being arranged 

 in straight as well as oblique transverse series ; and on some rays near 

 the base, on either side of the midradial area, a less regular arrange- 

 ment in longitudinal fines is observable. Each plate is raised into a 

 low convex tabulum equal to or lower than its width at top, sur- 

 mounted by a dense brush or group of very numerous and diverging 

 delicate spicules. These spicules or spinelets are more delicate and 

 slender than any to be found elsewhere in the Asteroidea. They vary 

 in length from 0.75 mm. to 0.975 mm., and the articulating base is 

 about 0.06 mm. thick, and thence tapers toward the tip, near which 

 the spinelet is 0.0155 mm. thick. The distal three-fourths or four- 

 fifths of each spicule is clear and glassy, only the basal part being 

 reticulated, or perforated, in the characteristic way. The epidermis 



