AGASSIZ AND CLARK: REPORT ON ECHINI. 257 



did not regard the Indian form as luzonica. Comparison of the Hawaiian speci- 

 mens of Oldhami and luzonica reveals several apparently constant differences which 

 warrant their separation. In luzonica, the breadth of the test is usually .80— .85 of 

 the length, though it may be more ; in Oldhami it is over .90. In luzonica the 

 width of the area enclosed by the peripetalous fasciole is about .50 of its length, 

 rarely more than .55 ; in Oldhami it is .60-.70. In luzonica the height of the 

 subanal fasciole is about .50 of its horizontal breadth ; in Oldhami it is rarely over 

 .40. The actinostome is more deeply sunken and the labrum is more prominent 

 and more nearly pointed in Oldhami than in luzonica. The petals are slightly 

 broader and the lateral petals are a little longer, and are more noticeably depressed 

 below the fasciole, in Oldhami. It is evident therefore that this species is nearer 

 lyrifera than luzonica is, but it agrees closely with the latter in color and fragility 

 of the test. The largest specimens are about 50 x 45 mm. 



Station 3824. Off Lae-o Ka Laau Light, Molokai, 222-498 fathoms. 



3826. Off Lae-o Ka Laau Light, Molokai, 371-430 fathoms. 



3839. Off Lae-o Ka Laau Light, Molokai, 259-266 fathoms. 



3842. Off Lae-o Ka Laau Light, Molokai, 495-506 fathoms. 



3863. Off Mokuhooniki Islet, Pailolo Channel, 127-154 fathoms. 



3892. Off Mokapu Islet, Molokai, 328-414 fathoms. 



3908. Off Diamond Head Light, Oahu, 304-308 fathoms. 



3912. Off Diamond Head Light, Oahu, 310-334 fathoms. 



3916. Off Diamond Head Light, Oahu, 299-330 fathoms. 



3917. Off Diamond Head Light, Oahu, 294-330 fathoms. 



3918. Off Diamond Head Light, Oahu, 257-294 fathoms. 

 3992. Off Mokuaeae Islet, Kauai, 528 fathoms. 

 3997. Off Ukula Point, Kauai, 418-429 fathoms. 

 4028. Off Ukula Point, Kauai, 444-478 fathoms. 

 4132. Off Hanamaulu, Kauai, 257-312 fathoms. 



Thirty-seven specimens. 



Brissopsis circosemita A. Ag. and Clark. 



We have given this name to a small Spatangoid, of which there is only a single 

 specimen, and that a bare test 17 mm. long, 14 mm. wide, and 11 mm. high. The 

 posterior extremity is truncate vertically. The plastron is slightly keeled pos- 

 teriorly. The labrum is nearly straight, and the actinostome is scarcely sunken. 

 The peripetalous fasciole and the petals are similar to those of a young luzonica, 

 but the subanal fasciole is unique. It is quite small and nearly circular, 5 mm. 

 in transverse diameter and 5.25 mm. vertically. A conspicuous branch arises 

 from the upper portion, on each side of the anal system, and runs to the posterior 

 portion of the peripetalous fasciole, which it joins in the posterior ambulacrum. 

 The two branches thus enclose the anal system, but are not very near to it. While 

 such anal fasciolar branches are not uncommon in Brissopsis, they are par- 

 ticularly distinct and complete in this specimen. Only three ambulacral plates 

 enter the subanal fasciole on each side. The abactinal system is very compact 

 vol. l. — No. 8 17 





