46 MARINE BIOLOGY OF THE SUDANESE RED SEA. 
specimen, which was obtained by the ‘ Challenger’ off Manila, the centro- 
dorsal is a saucer-shaped disc, marked with cirrus-sockets almost to the centre 
of the dorsal surface, and bears seventeen cirri in an irregular row around its’ 
margin. These have fifteen to seventeen or even nineteen ossicles, which 
gradually increase in length from the first to the seventh, beyond which they 
are scarcely longer than broad and increasingly compressed, and have slightly 
carinate dorsal edges or even a minute dorsal spine. 
In the specimens under notice the radials are distinctly visible, and are not 
in contact except at their proximal ends. In the type they are only just 
visible, but this point of difference is possibly due to the immature condition 
of the Suez specimens. The two primibrachs agree with those of the type. 
The arms of one of these specimens branch once only ; the other has two 
secundibrachs in one branch of each arm and, in the case of one arm, two 
tertiibrachs *. The third, eighth, and fourteenth joints are syzygies; others 
follow at intervals of four to five joints. 
The proximal pinnules have fewer ossicles than those of the type. That of 
the second brachial has fourteen, and that of the fourth fourteen or fifteen. 
The next pinnule (fifth brachial) is little larger than that of the second, but 
has fifteen or sixteen ossicles ; while that of the seventh brachial has eleven to 
twelve and is much smaller than that of the second. 
Locality—Suez Bay, 10 fathoms, mud. 
ANTEDON IMPARIPINNA, Carpenter. 
One specimen of this species was collected in Suez Bay and four in Suakim 
Harbour. In the former the dorsal surface of the centro-dorsal is simply 
flattened, but in the latter, especially the larger ones, it is concave, thus 
resembling the type. 
In the Suez specimen the total number of armlets is twenty-seven ; while 
those from Suakim have twenty-one, twenty-one, twenty-six, and thirty- 
three, respectively. 
In the Suez specimen the second syzygy occurs at the seventeenth to the 
nineteenth joint, and others follow at intervals of eight to nine joints. In 
several of the arms of the specimens from Suakim, syzygies occur at the 
eighth and twelfth joints, and in several of the arms of the larger specimens 
the second syzygy is at the twentieth. 
Colour in life, as noted by Mr. Crossland,—Suakim specimens : (a) purple 
and yellowish white ; (6) brown and white ; (¢) light brown and white ; 
(d) a uniform deep brown; Suez specimen, predominantly yellow. This 
last specimen had a brown commensal Polynoid living upon it. When taken 
from the water the tegmen and viscera were detached spontaneously. 
Distribution.—Bay of Amboina, Tonga Islands, Batjan, Hongkong, New 
Guinea (Hartlaub), Red Sea. 
* A more precise description of these specimens is not possible owing to their imperfect 
condition. 
