CHAP. U1. ] THE CRUISES OF THE ‘ PORCUPINE,’ a 
of the adjacent arm, so that the angles between the 
arms are entirely filled up by a delicate membrane 
stretched on and supported by spines, and the body 
thus becomes regularly pentagonal. There is no trace 
on the ventral surface of the arms of the trans- 
verse ranges of membranous comb-like plates which 
are so characteristic in Pteraster. 
By far the most abundant and conspicuous forms 
among the star-fishes in deep water were the genera 
Astropecten and Archaster, and their allies. At one 
to two hundred fathoms the small form of Astro- 
pecten irregularis, A. acicularis of NORMAN, literally 
swarmed in some places, usually in company with 
the small form of Luwidia savignu, M. and T., L. 
sarsii, D. and K. I feel no doubt that these two 
forms, A. acicularis and L. sarsii, are mere deep- 
water varieties of the forms which attain so much larger 
proportions in shallow water. The late Mr. Edward 
Waller took charge of Mr. Gwyn Jeffreys’ yacht, 
during the summer of 1869, on a dredging cruise off 
the south coast of Ireland. He worked principally 
about the 100-fathom line and a little within it, and 
procured a magnificent series both of Astropecten and 
Iuidia showing a gradual transition through all 
intermediate stages between the large and the small 
varieties. 
The cold area gave us Astropecten tenuispinus in 
great abundance and beauty. The tangles sometimes 
came up scarlet with them, and associated with this 
species a handsome new form of a peculiar leaden 
grey colour, and with paxille arranged on the 
dorsal surface of the disk in the form of a rosette, or 
the petaloid ambulacra of a Clypeaster. Astropecten 
