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



Islands, those from the two last-named localities being nearly all young forms. The 

 majority of the examples from Kerguelen are considerably larger than the type form 

 described by Mr. Smith, which was also collected at Kerguelen, during the sojourn of the 

 Transit of Venus Expedition in 1875. The largest specimen dredged by the Challenger 

 measures R= 68-70 mm.; r = 27 mm.; another example, R = 60 mm.; r = 23 mm. I 

 have figured one of these examples. 



I have failed to detect any pedicellarise in this species, although it is distinctly stated 

 in Mr. Smith's diagnosis that numerous large ones occur in the interspaces between the 

 paxillae on the abactinal area. Numerous large and conspicuous papulae are present in 

 all these interspaces, and I venture to suggest with little hesitation that these are the 

 organs referred to, the word " pedicellariis " having probably slipped in inadvertently. 



Young Phase. — The small examples taken off Marion and Heard Islands exhibit so 

 unmistakably the characters of the adult, that I feel little or no hesitation in assigning 

 them to this species, notwithstanding their being found in association with Gnathaster 

 elongatus. It is to be confessed, however, that I should have shrunk from expressing an 

 opinion so definitely if the young of Gnathaster elongatus had been unknown, but fortu- 

 nately small examples of that species were found at Marion Island and Kerguelen, which on 

 their part resemble so characteristically the adult form of their species, and are so readily 

 distinguishable from the young examples of the same size of Gnathaster meridionalis, as 

 to place the question almost beyond doubt. I have given figures of the young of both 

 species, see PI. XIX. and PI. XLVIII. The adult forms are drawn on PI. XL VII. and 

 PI. XLVIII. 



2. Gnathaster elongatus, n. sp. (PI. XLVIII. figs. 1-4; PI. XLIX. figs. 5-10; PI. 

 XIX. figs. 5 and 6). 



Rays five. R = 56 mm.; r=16"5 mm. (Another example, R=62 mm.; r=l7 

 mm.) R = 35 r approximately. Breadth of a ray between the second and third supero- 

 marginal plates, 14 "5 mm. 



Rays long, narrow throughout and tapering for the genus. General form subdepressed. 

 Abactinal area capable of slight inflation, often producing the effect of carination along 

 the ray. Actinal area subconvex, especially apparent along the ray. Margin thin but 

 rounded outwardly. Interbrachial arcs wide and open, but often with a slight tendency 

 to become angular at the summit of the arc. 



The whole abactinal paxillar area is covered with low and rather distinctly spaced 

 pseudo-paxillse, leaving small spaces for the protrusion of the papulas. The crown or 

 tabulum of the paxilla is subcircular and bears nine to twelve or more very short papilli- 

 form granules, of which one to three are central ; these are coarse, subprismatic, roundly 

 truncate, all perfectly uniform in height, size, and character, and are not specially crowded 



