106 Papers from the Department of Marine Biology. 
long, rather stout; no segments longer than wide; 10 to 12 distal segments with 
conspicuous longitudinal dorsal crests or teeth; opposing claw large. Arms 
10, the I Br series and first two brachials with small ventro-lateral processes. 
Arms about 25 mm. long, composed of about 50 to 60 brachials, which are more 
or less quadrate and are distinctly longer than wide on distal part of arm; 
syzygies between 3-4, 9-10, and then at intervals of 6 to 9 joints. P, less than 
2 mm. long, composed of 10 or 11 short joints, the basal ones squarish; Pa 
similar but much smaller and with only 6 segments. Pe» similar to P, but 
more than 2 mm. long, rather stout, with 10 joints, decidedly the largest 
pinnule on the arm; P, about equal to P, or a trifle larger, but with fewer 
joints; distal edges of segments of P2 and P, somewhat flaring, very minutely 
spiny. Ps; smaller than P, and with only 6 joints; P, similar but smaller. 
Succeeding pinnules gradually larger, until at middle of arm they are about 
3 mm. long and have 12 segments. None of the basal pinnules are rigid and 
spike-like, but all have rather flagellate tips. Color, purple of a rather pale 
shade; pinnules yellowish at tips; cirri more or less white. Colors fairly well 
preserved in alcohol. 
The single specimen, upon which this species is based, was picked up on 
the sand flat, on the southern side of Friday Island, at low tide. Its relation- 
ships are obscure, for although it seems to be a member of the Himerometride, 
the outer brachials preclude its being placed in Amphimetra, while the known 
species of Heterometra all have more than 10 arms. It may perhaps need a 
generic name of its own. 
21. Tropiometra afra (Hartlaub). 
Not common, but a few specimens were found on the extreme outer margin 
of the southwestern reef-flat at Maér. 
22. Iridometra nana (Hartlaub). 
A very active comatulid, purplish-black with light brown cirri, was taken 
on the southwestern reef at Maér, October 10. The arms are 40 to 45 mm. long. 
It is apparently an Jridometra, and, except for the distinctive color, which is 
well preserved in alcohol, it answers well to Hartlaub’s description of nana. 
