3fi() METALIA. 



with "deep, odd ambulacra! groove? instead of being placed in the same subdi- 

 vision as E. mediterraneum. Tbe genus Kleinia I am unable from Gray's 

 specimens to distinguish from Brissopsis. Meoma grandis Gray, from a care- 

 ful comparison of the originals of Gray, I consider as identical with Meoma 

 nigra [Kleinia nigra A. Ac). The locality quoted by Gray is undoubtedly 

 erroneous, Captain Belcher, as Liitken mentions in his '• Bidrag," having 

 visited Central America ; and the fact that we have in the British Museum, 

 brought back by Belcher, an Agassizia subrotunda Gray, Meoma grandis 

 Gray, and an EcMnantkus testudinarius Gray, marked "Australia," neither of 

 which can be distinguished from Agassizia ovulum, Meoma nigra, and 

 Clypeaster speciosus, found upon the west coast of Central America, seems to 

 indicate without much doifbt an error in the localities of the specimens of 

 ( i rav's Catalogue. 



Littoral to 85 fathoms. 



(BRISSUS.) Metalia. 



Metalia Okay. 1855. Cat. Rec. Ech. (emend.) 



The subgenera Plagionotus and Metalia are united as a single subgenus of 

 Brissus (Metalia). The slight differences in the course of the peripetaloua 

 fasciole and the presence of larger tubercles not being sufficient ground, with 

 our present knowledge of the changes due to growth, to warrant retaining 

 them both, and as Plagionotus is already in use among Coleoptera, the sub- 

 genus proposed by Gray has been adopted and emended to include Bris udae 

 having a more or less broad, elliptical, or undulating re-entering peripetaloua 

 fasciole, and an anterior ambulacral groove. Lateral ambulacral petals 

 narrow, elongate ; pores well separated; apex anterior ; actinal plastron nar- 

 row, heart-shaped ; subanal area bordered by a broad fasciole, with anal 

 branches connected with it ; subanal ambulacral pores sending radiating 

 grooves towards the centre of the subanal area. Actinostome anterior, 

 crescent-shaped. Tuberculation in the peripetalous fasciole coarse, frequent- 

 ly consisting of primary tubercles. Spines short, slender, curved ; those of 

 actinal surface longer, curved, broad at base of milled ring. Ilaime sug- 

 gested the propriety of uniting Eupatagus with Plagionotus, but as Desor 

 justly notices, the difference in structure of the ambulacra shows that they 

 have only superficial characters in common, Eupatagus being closely allied 

 to Spatangus, and not to Brissus. as is the case with Plagionotus. 



