CHAP. V.] THE GULF-STREAM. B51 
shows very distinctly, as in Calveria, that the ambulacral ranges 
of plates are essentially wthin the inter-ambulacral (Fig. 96). 
The specimen examined was slightly distorted. 
On Saturday, the 3d, we sounded in 1240 fathoms and low- 
ered the dredge, which again gave us a very full sample of the 
fauna. Star-fishes allied to the genus Archaster were once 
more most prominent, and among these were several specimens 
of a very beautiful little sea-star, which I propose to name Por- 
cellanaster ceruleus, most nearly allied to Ctenodiscus, but pre- 
senting many marked differences. The disk in a full-sized ex- 
ample is about 20 mm. in diameter, and the length of the arms 
nearly equals the diameter of the disk. The ad-ambulacral 
plates are large, and each bears usually two flattened somewhat 
Fic. 96.—A ceste bellidifera, Wyvittt Tuomson. Inner surface of the test. Twice the natural 
size. (No. 44.) 
irregularly shaped spines. Those plates forming the angles of 
the mouth are unusually flattened and expanded. The mar- 
ginal plates are of large size, and arranged in two rows. The 
surface is finely granular, and each plate of the upper series 
bears near its inner edge a rounded tubercle. The two termi- 
