BCHINODBBMA. '.' 



margin very .sharp, the inner actinal ambulacralfl with spines, the oral angle provided 

 with a large spine. While the specific characters would appear to be that the longer 

 radius is more than twice as long as the shorter radius, the marginal plates are MTV 

 numerous, and the innermost ambulacra] spine is spatulate and fluted at its free end. 



The smallest specimen has not quite acquired the generic characters of the larger; 

 the abactinal integument is not so thick as to altogether hide the superficial granules, 

 and the granules on the actinal interambulacra have not developed into spines, so that 

 there is no marked difference between the outer and the inner parts of these areas. 



PEXTAGONASTER INCERITS. 



The single small specimen, is, I think, an ally of the Australian species of Penta- 

 gonaster (sens, lat.}, but the arms are proportionately longer than they generally are 

 in this genus ; it is, possiblv, an immature specimen in which R would gradually 

 increase in proportion to r. If it should prove to be an adult, its proportions mav be 

 compared to those of P. duebeni and P. </nnni; it is, however, to be distinguished bv 

 the fact that there are no large plates on the actinal inter-radial areas, the plates being 

 of the character of, and a little larger than, the small squarish granular plates which 

 bound the marginals; these last number about 12/14 for the side of each arm, and 

 are completed by a large terminal ; there are two rows of well-developed spines at the 

 sides of the ambulacra ; those of the inner row are nearly twice as long and as 

 numerous as the outer. I propose to call this form Pentaijonastcr incertus ; it was 

 taken at 9G-120 fms., in MacMurdo Bay. 



LKPTOPTYCHASTER KERGUELENENSIS. 



/i/i/r/iHxfer km/iirlt'iu'iixi*, K. \. Smith, Phil. Trans. 108 (187!)), p. L'T.s, pi. xvii. 2 ; Sladen, ('hall. 

 Rep. Ast. (l.s.x'.i), p. ]8h Bell, Mar. Invert. S. Africa iii. (1!)0:>) p. ->\->. 

 (Hitarctii'iix, Sladen, n/>. fit. p. 190. 



I must own to some temerity in associating a specimen in which R = 212 and 

 r = 58 with a species whose type had Li = 38 and r = 12 '5, and a representative 

 of which, hardly much larger, was found to be bearing young; but even the most 

 recent writers on Echinoderms have not yet promulgated the. doctrine that difference 

 in size is a specific character, though I am not quite sure that in practice they do 

 not sometimes act as though they had. However, one has only to get a clear idea 

 of the essential characters of this genus to feel sure that one lias it here ; as to specific 

 characters, it is first to be said that most of the L. kerguelpnensis material is badly 

 preserved, while the condition of L. niifdrrticus is particularly good. Though the 

 differences between the two species appear, from Mr. Sladen's lengthy description, to 

 be considerable, it will, I think, be found on examination of the specimens preserved 

 in the Museum, that L. <iiitnr<-ti<-ii!< is but the expression of some earlv stages of 

 L. kerguelenensis. It will be remembered that both "species" come from closely 

 adjacent localities. At any rate, we now know that the specimens of L. antarcticus 



