1881.] THE SURVEY OF H.M.S. ' ALERT.' 95 



it will be easy enough to call it L. luetkeni. I add the following 

 short description : — 



Perfectly flat, with twenty-three completely developed and three 

 less-well-developed arms ; brown above, with a dark line runninc 

 round the disk, cream-white below ; the arms are very slender, and 

 widest at some little distance from their point of insertion into the 

 disk. The small and white madreporic plate Hes near the dark 

 circular line, and is fringed with a few spines. The spines on the 

 arms form a median and a lateral series ; but the former does not 

 extend along the whole length of the ray ; the arms themselves have 

 the appearance of being ringed externally, owing to the transverse 

 disposition of these spines ; single or bifurcate spines, not very 

 regularly arranged, are to be found on the disk, but are not 

 numerous. i2 = 51 o, r= 14. 



Trinidad Channel, 30 fathoms. 



It is of interest to point out that in the three partly developed 

 arms the ambulacra! suckers are closely packed, and do not exhibit a 

 definitely paired so much as a pycnopod arrangement ; and this, 

 which is characteristic of the adult Asterias, is pro tanto of value 

 in supporting Dr. Liitken's view as to the affinities of the genus 

 now under examination. The fact of the presence of three arms 

 smaller than the rest should, further, be compared with the remarks 

 on this subject made by Dr. Liitken (and translated in Ann. & Mag. 

 Nat. Hist. ser. 4, xii. p. 336). 



Pentagonaster singularis, M. & Tr. 



Goniodisciis singularis, Miiller & Troschel, Archiv fiir Naturg. 

 (1843) ix. p. 116. 



Pentagonaster singularis, Perrier, Rev. des Stell. p. 222. 



One specimen, obtained in Tom Bay, 0-30 fathoms ; bottom, 

 rock, kelp, and mud. 



This specimen is interesting as being intermediate in size between 

 the two specimens already possessed by the Museum, and collected 

 by Dr. Cunningham. 



Pentagonaster paxillosus. 



Astrogonium ^axillosum. Gray, P. Z. S. 1847, p. 79. 



Pentagonaster paxillosus, Perrier, Rev. Stell. p. 221. 



A small specimen (72 = 19, r=12; 20 infero-marginal plates), 

 collected by Dr. Cunningham at Sandy Point, must be referred to 

 this species. If it be distinct from it, the distinctive specific characters 

 are not differentiated ; the condition of the type specimen, which is 

 dry, prevents a determination of the question whether the Australian 

 form has a glassy spine at each angle of the mouth. If it shall 

 prove to be absent, that character might perhaps be shown to be 

 one of specific value, and would, at any rate, afford a point of 

 distinction between the South-American and the Australian form. 



Calliderma grayi, sp. n. (Plate VIII. fig. 5.) 



Arms not long, interbrachial angle rounded ; 72=1."), 7"=8. Ten 



