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 l less than 



2 mm. long, composed of 10 or 11 short joints, the basal ones squarish; P a 

 similar but much smaller and with only 6 segments. P 2 similar to P! but 

 more than 2 mm. long, rather stout, with 10 joints, decidedly the largest 

 pinnule on the arm; P 6 about equal to PI or a trifle larger, but with fewer 

 joints; distal edges of segments of P 2 and P 6 somewhat flaring, very minutely 

 spiny. PS smaller than PI and with only 6 joints; P c 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 Himerometridse, 

 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 Maer. 



22. Iridometra nana (Hartlaub). 



A very active comatulid, purplish-black with light brown cirri, was taken 

 on the southwestern reef at Maer, October 10. The arms are 40 to 45 mm. long. 

 It is apparently an Iridometra, and, except for the distinctive color, which is 

 well preserved in alcohol, it answers well to Hartlaub's description of nana. 



