446 THE VOYAGE OF H.M.S. CHALLENGER. 



"Knight Errant" dredgings, can I recognise an identity with the specimens described by 

 the eminent Norwegian naturalists. Judging from the description above cited, it seems to 

 me that the variety septentrionalis occupies an intermediate position between the typical 

 form of Crossaster pap>posus and the Solaster affinis of Danielssen and Koren, and this 

 circumstance previously led me 1 to express the opinion that the latter form might be a 

 locational variety of the type of Crossaster papp>osus. 



2. Crossaster penicillatus, n. sp. (PL LXX. fig. 5; PL LXXII. figs. 9 and 10). 



Rays nine. R = 34 to 36 mm.; r=12 mm. R<3 r. Breadth of a ray near the 

 base, 6 mm. 



Rays narrow and rather attenuate, more or less arched abactinally and with a tendency 

 to be carinated on the outer part. Disk slightly inflated. Interbrachial arcs rounded. 



Abactinal area with small delicate plates forming a reticulated network with wide 

 meshes, bearing small, rather widely spaced paxilliform tufts of spinelets,' articulated on a 

 tubercular base. The larger paxillse on the disk and at the base of the rays have a crown 

 of about ten or more spinelets, five or six being long and needle-like, the rest much 

 shorter. From two to four large isolated papulae occur in the meshes. No definite order 

 of arrangement is discernible in the disposition of the paxillse. 



The marginal plates (the representatives of the infero-marginal series) are large and 

 very widely spaced, and resemble greatly enlarged paxillse. The base is thick and large, 

 slightly compressed (the major axis being placed obliquely in relation to the axis of the 

 ray) and bears a crown of about twelve to fifteen needle-like spinelets. 



The armature of the adambulacral plates consists of two series of spinelets. (1.) A 

 furrow series of four or five elongate spinelets united for a short distance at their base 

 by a delicate membranous web, and forming a fan directed over the ambulacral furrow. 

 (2.) A transverse lineal series of seven or eight long robust spines, longer than those of the 

 furrow series, which may form either a straight or a slightly curved line on the actinal 

 surface of the plate. These spinelets diminish in size at the outer end of the series, and 

 are united for a short distance at their base by a delicate membranous web. 



The mouth-plates are large and the united pair have a spade-shaped outline. Their 

 armature consists of a marginal series of about nine elongate spinelets on each plate, the 

 innermost one being larger and more robust than the others, which diminish a little in 

 size as they recede from the mouth, and are rather smaller than the furrow series of 

 spinelets on the adambulacral plates generally. They are united for a short distance at 

 their base by a delicate membranous web, and form a slightly scoop-like marginal fringe. 

 On the actinal surface of each plate are seven or eight elongate spinelets in a slightly 

 curved hneal series, but sometimes irregular at the inner end of the series, where three 

 spinelets may simulate a transverse series. 



1 Memoir of the Echinoderniata of the Arctic Sea to the West of Greenland, London, 1881, p. 39. 



