576 BULLETIN 82, UNITED STATES NATIONAL MUSEUM. 



The figure given by Carpenter shows a crown 3.5 mm. long, which closely 

 resembles that of the species of Hathrometra in the corresponding stage. The 

 basals are high and the radials very wide, while the IB^ and IBr 2 are relatively 

 long and narrow, though a considerable number of brachials is developed beyond 

 them. There are no traces of an ambulacral skeleton. 



There appear to be six very short discoidal columnals immediately beneath the 

 calyx. From the ninth onward the columnals are greatly elongated, with the 

 median annulus prominent. 



The orals, shaped like those of the species of Hathrometra, are relatively 

 small. 



There is little doubt that this pentacrinoid is the young of a species of Thau- 

 matometra, an abyssal genus closely related to Hathrometra. 



DOUBTFUL SPECIES. 



In 1901 Professor Ijima recorded that a small stalked crinoid was taken from 

 the carapace of a specimen of the giant crab (Macrocheira kaempferi) caught in 

 Sagami Bay. 



Wishing if possible to obtain some clue as to what this small stalked crinoid 

 might be I wrote to Prof. H. Matsumoto, of Sendai University (then of the 

 Imperial University at Tokyo), and from him I received the following letter: 



I have examined Professor Ijima's crinoid. The unique specimen represents the penta- 

 crinoid stage of a eomatulid, which may possibly be a Psathyrometra, though belonging to a 

 species as yet unknown. 



Description. Column 17 mm. long, composed of 32 segments, which are elongated and 

 " dice-box shaped " except for the proximal 6, which are very short and discoidal. 



Cirri X in number, arranged in two (a radial and an interradial) circlets. 3 mm. long, 

 composed of 10 or 11 segments which are elongated, " dice-box shaped," wider distally than 

 proximally. All the cirrus segments are longer than wide, the third-fifth being the longest ; 

 the distal edges of the segments are produced and overlap the bases of the succeeding; there 

 are no dorsal spines ; the opposing spine is minute, terminally situated ; the terminal claw is 

 long and stout In addition to these 10 cirri there is a very rudimentary one, radially situated. 



Basals just visible, triangular. 



Kadials well developed, forming a complete closed circlet. Their external surfaces are 

 very rough, and there is a row of spines along their distal margins. 



Elements of the IBr series narrow and widely separated. 



IBn narrower distally than proximally, the surface very rough, the lateral and distal 

 margins armed with prominent spines. Axillaries rhomboidal, longer than broad, with very 

 rough surfaces, and with especially prominent spines on the lateral borders and along the 

 distal edges. 



Arms, 10 in number, about 10 mm. long; brachials longer than broad, "dice-box shaped," 

 the first four or five with rough surfaces, the spines being especially prominent along the dorsal 

 side; fifth-fourteenth brachials with a very prominent spine on the distal border in the median 

 line. 



Syzygies occur between the third and fourth, eleventh and twelfth (or ninth and tenth), 

 sixteenth and seventeenth, and twentieth and twenty-first brachials. 



Pi, on the second brachial, as yet rudimentary, 0.7 mm. long, composed of three or four 

 much elongated segments with rough surfaces. The first and second segments are about twice 

 as long as broad, "dice-box shaped"; the third segment is half again as long as broad; the 



