58 BULLETIN OF THE ZOOLOGICAL MUSEUM 



Mcera stygia.* 



In the British Museum and Copenhague Museum are specimens of a 

 Moera allied to M. atropos, holding to it the same relation which Echi- 

 nocardium gibbosum holds to E. cordatum. The test has a short, lon- 

 gitudinal diameter, is remarkable for the great height of the abactinal 

 axis, the sharply truncated anterior extremity, the narrow lateral am- 

 bulacra, the elongate anal system, and the prolongation of the anal 

 plastron in a sharp keel. 



A specimen in the Mus. Comp. Zool. is said to have come from the 

 Red Sea. 



Rhynobrissus pyramidalis. 



I am indebted to Mr. Thomas J. Moore for a specimen of this remark- 

 able Spatangoid. It is allied to Brissopsis, having like it a peripetalous 

 fasciole (narrow), a subanal and anal fasciole (broad) ; it has, however, 

 no anterior groove, the test being uniformly convex anteriorly, the vertex 

 is posterior slightly in advance of the bevelled posterior extremity. The 

 anal plastron is heart-shaped, somewhat as in Metalia, projecting like a 

 keel beyond the outline. Seen from above, the outline of test is dia- 

 mond-shaped, rounded anteriorly. The ambulacral petals but slightly 

 sunken, resembling those of Faorina. The actinostome is crescent- 

 shape, very narrow, extends well across the test, immediately sur- 

 rounded by a broad, bare space, which forms rapidly narrowing bare 

 ambulacral spaces on each side of the narrow elongate actinal plastron. 

 The spines of the lower surface are long, curved, and slender, while 

 those of the rest of the test are short, hair-like ; their coloring is light 

 violet. The anal fasciole is open above the anal system, but a secondary 

 subanal plastron is formed independent of the principal one by a broad 

 band passing below the anal system, slightly above the origin of the 

 anal fasciole, — a feature which thus far has not been noticed in any 

 other genus of Spatangoids, finding its parallel only in the double branch 

 of the anterior part of the peripetalous fasciole of Faorina. 



Free Public Museum (Liverpool) ; Mus. Comp. Zool. — Linguin. 

 China Seas. 



Cambridge, January 10, 1872. 



* Liitken MS. in litt. 



