I'd 1 Hi U.KI IN 82, I MTED STATES N.VI [ONAL MUSEUM 



Ontpadoiiutra mortenti GisiJn, Kungl. Fysiogr. Sallak. Handl., new ser., vol. 45, No. 11, 1034, 

 p. 23. 



mostic features.- Tho enlarged proximal pinnules are very stout and taper 

 rapidly to the tip; in fully developed individuals they are composed of about 20 seg- 

 ments the distnl ends of which project abruptly beyond, but do not overlap, the bases 

 of t ho segments succeeding and are armed with very numerous fine spines, which in 

 large specimens may be confined to the outer segments; the distal ends of the proxi- 

 mal brachials are very strongly produced and everted so that the arm bases are very 

 rough. There are 28-43 (usually 30-34) arms, which are 70-124 (usually 90-110) 

 nun. long. 



Description. — The centrodorsal is thick discoidal with the bare polar area rather 

 small and concave, bearing 35-40 cirrus sockets in about three irregular and closely 

 set rows about its margin, the distalmost cirrus sockets encroaching somewhat on the 

 dorsal polar area. 



The cirri are XV XXXV, 28-40 (usually about 30), 23-37 (usually about 30) 

 mm. long, large and stout. The segments are all somewhat broader than long and 

 those in the distal half of the cirri bear small dorsal spines. 



The radials are only very slightly, if at all, visible. The IBr t are short and are 

 partially united laterally. The IBr 2 (axillaries) are short, pentagonal, dorsally 

 rounded, and widely free laterally. The IBr series are 4(3+4), occasionally 2. The 

 lllBr series are commonly 2 interiorly and 4(3+4) exteriorly, but this is by no means 

 an invariable rule. When less than the full number of IIIBr series is developed on a 

 postradial series it is the outer ones that are lacking; in small specimens only the two 

 inner may be present. The elements of tho division series have a peculiar swollen 

 appearance; while this feature occurs in all the species of Ilimerometra it is especially 

 noticeable in this form. 



Tho arms are 28-43 (usually 30-40) in number and are 70-124 (usually 90-110) 

 mm. in length. Tho brachials are very uniform and short, discoidal, the first five or 

 six being somewhat longer in proportion than the others, which are very short. All 

 the brachials have overlapping and slightly everted distal edges, which give the arms 

 B \ery rough appearance. 



Syzygies occur between brachials 3+4, again from between brachials 23+24 to 

 between braciuals 31+32, and distally at intervals of 13 to 16 muscular articulations. 



The pinnules on the division series and P, are enormously thickened, slightly 

 recurved, and hornlike, with about 20 short cylindrical segments which are about as 

 long as broad. Tho distal ends of the segments are markedly broader than the bases 

 of the segments following so that the profile of the pinnules shows a series of abrupt 

 Bteps; they are usually abundantly armed with fine spines, though in large individuals 

 they may be simply roughened except in the distal portion of the pinnules. P D is 

 about 20 mm. long, and the pinnules succeeding decrease in length to Pi, which is 

 aboul It, mni. long. Tho pinnules of the inner arms are somewhat smaller than those 

 of the outer. The following pinnules are slender, decreasing in length to about P 6 , 

 then gradually increasing again, reaching a length of 10 mm. distally. 



The color in alcohol is flesh color; no markings are recorded on any specimen. 



Notts. — The type specimen was described by Ilartlaub as follows: The centro- 

 dorsal is a thick disk with a flat bare dorsal pole, bearing cirri in two rows. Tho cirri 



