82 Natural History" Bulletin. 



beautiful objects under a low power of the microscope than 

 these glassy spined ophiurans. For some reason they are 

 particular!}- apt to be provided with conspicuous radiating 

 bands of color, giving a remarkably elegant pattern against 

 which the pure transparent spines are outlined. Another fact 

 worth noting is that, so far as the writer has been able to 

 discover, these glassy spines are never colored, as are the 

 gorgeous calcareous spicules of the Gorgonid.^. for instance. 

 Nature has infinite resources, and the contrast of color is 

 probablv just as effective in the one case as in the other. 

 There mav be little significance in the fact that a deep violet 

 or purple is perhaps the commonest color in spicules of gorgo- 

 nians. and is also found in the conspicuous color bands on the 

 disks of manv species of glassy spined ophiurans. 



Perhaps the most remarkable spines possessed by any 

 species dredged from the pentacrinus grounds, are those of 

 an Ophiocamax ( ?j, in which some of the arm-spines are six 

 times the diameter of the arm in length. These beautiful 

 spines are beset with symmetrically arranged spinelets sharp 

 as needles (how poor the comparison!), and set nearh- at 

 right angles to the main shaft. The disk of this species is 

 remarkable for being highly vaulted and sharply divided into 

 five swollen lobes. The mouth-papillae are arranged in 

 rosette-shaped tufts, and tooth-papillae are present. Taken as 

 a whole the Ophiurid^ secured at this station are character- 

 ized by the paleness of their colors, although bright pigment 

 is b}- no means wanting. 



Among the Echini a number of striking forms were 

 secured. Perhaps the handsomest species was Porocidaris 

 sharreri, one specimen being a truly magnificent one, with 

 spines about seven inches in length, and the peculiar serrated 

 radioles resembling some of the ivory spear-heads used in 

 Africa. Dorocidaris barlletti exhibited remarkable variation 

 in its radioles or primar}' spines, those in young specimens 

 being conspicuously banded with scarlet and white, and 

 coarsely serrated, while the older and longer spines appear ta 

 have lost both their color and their serrations. 



