ASTEROIDEA 137 



crals usually have 2 spinelets; the others 3, 2, or i, with a scattering having 4 or 5, 

 rarely 6 or 7. In this specimen the membrane of the abactinal plates and spinelets is 

 decidedly inflated, perhaps unnaturally so. Fine, rather deep meandering grooves 

 traverse the actinal area from betw^een the inferomarginal plates to the ambulacral 

 furrowr, passing betw^een the adambulacrals. 



Sladen's small figure gives a misleading idea of the uniformity of the adambulacral 

 armature. The pair of much smaller spinelets which he mentions as occurring on the 

 outer part of the plate really belongs to the first series of actinal plates. They disappear 

 as soon as the inferomarginals come directly in contact with the adambulacral plates. 

 The simplest armature is a transverse series of 3, the furrow spinelet robust, 17 mm. 

 long, strongly compressed distally, often truncate, more heavily sheathed at base than at 

 tip. The second and third are decreasingly smaller (e.g. 1-4 and 0-85 mm.) and are 

 rather similar to actinal spines (see figs. 2^-2/ enlarged only > 40). When there are 4 

 adambulacral spines the fourth usually stands with the third in a longiseries along outer 

 margin of plate or on the aboral margin opposite the interval between the second and 

 third spines. Rather rarely there are 5 spines: an oblique transverse series of 3 and 

 aboral to the outer 2 (the subambulacrals) 2 other similar subambulacrals. It may be 

 stated here that the adambulacral armature of this species conforms absolutely to that of 

 Koehler's Cryaster, even to the spatulate furrow spine. 



Each mouth-plate has 3 or 4 marginal spines, the innermost the largest, and 3 or 4 

 smaller suborals closely crowded on the small plates. The marginal spines are generally 

 compressed, but are sometimes subclavate. 



The ambulacral furrows are narrow and the tube-feet are not in the least crowded as 

 they are in Perktiaster aurorae. 



The gonads are subspherical, about 3 mm. in diameter. The gonoduct passes upward 

 for a short distance and opens on the dorsal surface near ambitus. It should be recalled 

 that the inferomarginals are actinal in position so that the gonopore is at least a third the 

 distance from inferomarginals to centre of disk. 



The inner surface of the abactinal body wall is a muscular sheet as in typical Cryaster, 

 but the abactinal plates are rather larger than in comparable specimens of antarcticiis . 



I strongly suspect that Cribrellopsis rallieri Koehler, which was collected at Kerguelen, 

 at low tide or in very shallow water, is a close relative of Perknaster fusais despite the re- 

 ported presence of actinal papulae. Only a comparison of specimens can settle the question. 



Type locality. Kerguelen Island (off Royal Sound), 25 fathoms, volcanic mud. 



Distribution. Typical race known only from region of Kerguelen and Heard Islands, 



25-75 fathoms. 



Perknaster fuscus antarcticus (Koehler) 



(Fig. B, i-irt; Plate VI, fig. 2) 



Cryaster antarcticus Koehler, 1906, p. 24, pi. i, fig. i ; pi. 2, fig. 10.— 191 1, p. 28, pi. 4, figs, i, 2.— 

 1912, p. 30, pi. 3, figs. 6, 7.— 1920, p. 126, pi. 27, figs. 4, 7, 8-10; pi. 29, fig. I ; pi. 30, figs. I, 

 6; pi. 75, fig. 2. 

 St. 181. SchoIIaert Channel, Palmer Archipelago, 160-335 m., mud; 2 specimens. 



