»39 
The ends of the basal rays are visible as prominent rounded dorsoventrally elongate 
tubercles in the angles of the calyx. 
The distal borders of the radials are just visible beyond the edge of the centrodorsal ; 
they are strongly concave, curving upward over the ends of the basal rays and meeting just 
above them in the angles of the calyx ;. they are slightly produced outward, and are continued 
upward into very narrow interradial processes which entirely separate the IBtj. 
The IBr, are very short, chevron shaped, slightly less in median than in lateral length; 
the proximal edge is slightly swollen, the lateral edges slightly turned outward, straight, with 
a low blunt tubercle at the distal and proximal angles and sometimes a second near the former; 
the median line of the ossicle is occupied by a very high narrowly rounded crest, which is 
much higher proximally than distally. The IBr„ (axillaries) are irregularly rhombic, not quite 
twice as broad as long, with the distal and lateral angles rather strongly produced; the proximal 
half of the median line bears a narrowly rounded crest which is much lower than that on the 
IBrj; this crest posteriorly is of the same height as the anterior end of the crest on the IBr, 
whicii it adjoins; anteriorly it sinks gradually downward to the level of the general dorsal 
surface of the ossicle; the proximal borders of the IBr^ are, except laterally, slightly thickened 
and produced over the distal borders of the IBrj, and coarsely and obscurely scalloped; the 
distal edges are slightly everted, but not otherwise modified. 
The IIBr series are 2, resembling the IBr series but without any trace of carination or 
modification of the proximal or distal borders; the IIBr, bears a broad ventrolateral process, 
at the base nearly as wide as the segment, in height equal to about half the distance from 
the lateral margin to the median line, outwardly rounded, sometimes with one or two coarse 
low processes or blunt tubercles. 
The 20 arms, which are 70 mm. long from the border of the radials, resemble those 
of the other species of the genus; the brachials have rather prominent finely spinous distal ends. 
This individual only differs from the type of P. magnifica (which is before me) in the 
greater development of the keel on the IBr,, in the very faint keel on the IIBr series, and in 
the slightly longer proximal cirrus segments. It is undoubtedly a young example of that species. 
A third specimen of this interesting form was dredged by the "Albatross' at Stat. 5661. 
in I So fathoms in the Flores Sea (Cat. N" 35972 U.S. Nat. Mus.). 
IX. Family Th.alassometrid.ae A. H. Clark. 
Key to the Subfamilies of the Family Thalassometridae. 
a' P, shorter and smaller than P^, but similar to it (southern coast 
of Australia northward to southern j a [j a n ; 11 — 252 
Metres) P t i 1 o m e t r i 11 ae 
a- P, larger and longer than P., (Ca r i bbea n Sea a n d the Bay 
of B i s c a \' southward \.o Ascension and Tristan da 
