310 THE VOYAGE OF H.M.S. CHALLENGER 



Nymphaster basilicus is probably nearly related to the form described by Perrier under 

 the name of Pentagonaster ternalis l (which has subsequently been ranked by him as a 

 Dorigona '). So far as I can judge from the brief and general description, but excellent 

 figure, of Pentagonaster ternalis, the form under notice appears to me to be specifically 

 distinct. 



Genus Paragonaster, Sladen. 

 Paragonaster, Sladen in Narr. Chall. Exp. 1885, vol. i. p. 617. 



Disk small and pentagonal. Rays elongate, narrow, slender, and though tapering, 

 nearly uniform in breadth throughout. 



Supero-marginal plates separated from those of the opposite side of the ray by a single 

 lineal series of regular quadrate plates. Marginal plates of both series and the medio- 

 radial series of intermediate abactinal plates all uniformly granulated. The infero- 

 marginal plates, at least on the inner part of the ray, may bear a transverse series of small, 

 prominent, and more or less definite, spinelets. 



Abactinal area of the disk, which may be more or less inflated in the radial regions, 

 covered with uniform, hexagonal, tabulated plates, more or less paxilliform. 



Adambulacral plates broad, and bearing on their margins at right angles to the furrow 

 a number of small uniform spinelets, directed towards the adjacent plate, which form a 

 continuous series with the spinelets on the furrow margin of the plate, the last mentioned 

 spinelets being larger, flattened transversely, arranged in a semicircle, and radiating apart. 

 Within this marginally disposed armature, whose base-line forms a parabolic curve, a 

 transverse line of three or four isolated conical spinelets or papilla? may traverse the 

 breadth of the plate, or in a form where the plates are less broad, the spinelets or granules 

 may be more grouped and irregular in disposition. One spinelet on the outer part of the 

 plate may be longer and more prominent than the rest, but this character may not 

 extend beyond the inner half of the ray. 



Remarks. — The species which I have included in this genus have a decided and well- 

 marked facies, and may be at once distinguished from Nymphaster by the character of 

 the adambulacral armature, as well as by their general form. 



The starfish described by Perrier 3 under the name of Pentagonaster elongatus appears 

 to me from the description given to be nearly allied to this genus, and I have a strong 

 suspicion that it will ultimately prove to be Paragonaster. 



1 Bull. Mus. Comp. Zool., Harvard, 1881, vol. is., No. 1, p. 20; Nouv. Archives Mus. Uist. Nat., 2e Serie, 

 1884, t. vi. p. 233, pi. x. fig. 1. 



2 Ann. Sci. Nat. (Zool.), 1885, t. xix., Art. No. 8, p. 39. 



3 Ann. Sci. Nat. (Zool.), 1885, t. xix., Art. No. 8, p. 38. 



