AGASSIZ AND CLARK: RErORT ON ECHINI. 241 



Necker Island. 



Lanai Island. 



Puako Bay, Hawaii. 



Kamaliuo Bar, Niihau. 



Ivapeli, Maui. 



One hundred and tliree specimens. 



Eehinometra Mathaei Bl. 

 Echinus Mathaei de Blainville, 1825. Diet. Sci. Nat., 37, p. 94. 

 Eehinometra Mathaei de Blainville, 1834. Man. d'Actin., p. 225. 

 The series of Echinometras is quite easily divisible into two sets, one of which 

 consists of individuals with high, usually elongated tests, large tubercles, stout 

 spiues and relatively small (.17-23 of long diameter) abactiual system. These 

 are evidently the wide-ranging and common Mathaei (formerly called lucunter). 

 Honolulu reefs. 

 Kamaliuo Bay, Niihau. 

 Laysan Island. 



Station 3959. Off Laysan Island, 10 fathoms. 

 Thirteen specimens. 



Eehinometra picta A. Ag. and Clakk. 



The other set of Echiuometras has the test much flatter, the height rarely over 

 .50 of the long diameter, the abactiual system larger (.SA-.SO of tbe loug diam- 

 eter), the tubercles smaller, giving the abactiual surface a much more bare ap- 

 pearance than in Mathaei, and the spines longer and more slender. These two 

 forms are not sharply set otF from each other, but there are few individuals which 

 cauuot be distinguished at a glance, and it seems desirable to give the flat indi- 

 viduals a name. Similar specimens are in the Museum collection from the Society 

 Islands, but not from the East Indies, or west thereof. This species seems to 

 bear the same relation to Mathaei that viridis of the West Indies does to lucunter 

 (formerly called suhangularis). 



Honolulu reefs. 



Puako Bay, Hawaii. 



Necker Island. 



Kamaliuo Bay, Xiihau. 



Napeli, Maui. 



Station 3975. Off Necker Island Shoal, 16-171 fathoms. 



Twenty-nine specimens. 



Eehinometra oblonga Bl. 

 Echinus oblongus de Blainville, 1825. Diet. Sci. Nat., 37, p. 95. 

 Eehinometra oblonga de Blainville, 1834. Man. d'Actin., p. 225. 



A good series of this species was taken, none of which show the least approach 

 to mathaei or afford the slightest difficulty in identification, without refercuce to 

 the spicules iu the pedicels ! (vide de Meijere, 1904, and Doderleiu, 1906). 



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