NO. 19.] ECHINODERMS OF CONNECTICUT. 79 



extremely long, ciliated arms. Fig. 12 shows the larva of another 

 species, in which there are four bands of cilia in place of the long 

 arms. The metamorphosis is accomplished in a manner similar 

 to that described for the starfish. 



KEY TO SPECIES 



The ophiurans of the world are commonly divided into three 

 orders, distinguished by the character of the vertebrae. Only one 

 of these orders, the Zygophiurae, with interlocking vertebrae, is 

 represented in Long Island Sound. 



1. Spines on sides of arms short, and rather closely pressed 



against the arms Ophiura brevispina 



Spines projecting from sides of arms at a marked angle. .2 



2. Large median plates on upper side of arms surrounded by a 



series of small plates ; 5 or 6 spines on each side of each 



joint of arm Ophiopholis aculeata 



Median plates on upper side of arms directly in contact; 

 that is, not surrounded by small plates 3 



3. With 3 tooth-like projections (oral papillae) along each edge 



of each jaw; length of arms less than 10 times the 

 diameter of disk; radial shields in close contact 



Amphipholis squamata 



With 4 or 5 oral papillae on each edge of each jaw; length 



of arms more than 10 times the diameter of disk; radial 



shields separated 4 



4. Oral papillae 4 Amphioplus abditus 



Oral papillae 5 Amphioplus macilentus 



Ophiura brevispina Say, var. olivacea 



Green Ophiuran 



Plate I, fig. 5 ; Plates XIV, XV. 



This species, which was described by Say in 1825, is known 

 in the earlier writings of Lyman and Verrill under the name of 

 Ophiura olivacea. It has been found in shallow water at num- 

 erous localities along the Atlantic coast from Cape Cod to Brazil, 

 and at Bermuda. It is sometimes found, however, at a depth 

 of over a hundred fathoms, especially in the warmer regions. 



