306 Mr. E. A. Smith on a new Form of 



Greenwood in 1850, and the two others by Captain Stokes, 

 R.N., in 1855. 



In general aspect it reminds one at once of the genus 

 Ophiocoma, possessing a granular disk similar to that which 

 obtains in that genus; and the characters of the arm-plates and 

 of the t7-ue arm-spines are also congeneric ; but the difference 

 of the oral slits (rimee) and the presence of two or more 

 short flattened spines or scales which overlap one upon 

 another and upon the uppermost true arm-spine, tlius keeping 

 them almost in a horizontal position, are characters which 

 may be considered of sufficient importance to separate gene- 

 rically this curious species. The mouth-organs, namely the 

 teeth proper, tooth-papillge, and the jaws or framework which 

 supports them, are exactly similar to those of the genus 

 Ophiothrix ; also the oral fissures are precisely like those of 

 that genus — that is, are more in the form of wide , holes * than 

 narrow slits as in OpMocoma ; and the first ambulacral tenta- 

 cles are just within the rim^ and without scales. The side 

 mouth-shields are likewise of the same character as in OpMo- 

 ihrix^ and are situated along the lower margins of the oral 

 shields, as is almost invariably the case in that genus. How- 

 ever, the granular disk not showing radial shields, and the 

 presence of mouth-papillas, are differences which easily dis- 

 sociate the present genus from it. 



Ophioptekis *, gen. nov. 



Disk covered with a granulous skin as in OpMocoma ; 

 teeth, tooth-papillae, oral and adoral shields, and the mouth- 

 fissures as in Ophiotlirix ; oral papillae present ; brachial 

 shields and true spines similar to OpMocoma ; the arms pro- 

 vided with 2-3 compressed imbricating scales or compressed 

 spines above the uppermost spines ; two genital slits ; ambu- 

 lacral scales present. 



OpMopteris antipodum^ sp. nov. 



Disk roundly subpentagonal, somewhat lobed between the 

 rays, closely and coarsely granulated on the dorsal surface, 

 and beneath on the interbrachial spaces covered with crowded 

 short spines; rays 4^-5 times as long as the diameter of the disk; 

 oral shields small, somewhat heart-shaped, with a slight point 

 both on the inner and aboral sides; madreporic shield distinct, 

 larger than the others, and lobed a little on each side ; side 



* o0tf a snake and nrepn a fern. The rays call to mind the appearance 

 of certain kinds of ferns. 



