192 ME. W. PEECT SLADEN ON THE 



Pteraster, and support the whole actinal floor in Hymenaster, are 

 designated the actino-lateral spines. Finally, in the armature of 

 the mouth-plates distinction is made between (l)the mouth-spines 

 proper, which are situated ujjon the horizontal margins of the 

 plates, and which are usually directed over the actinostome ; and 

 (2) the secondary or superficial mouth-spines, which are borne 

 ujDon the surface of the plate, and usually stand perpendicular to 

 its plane — these latter spinelets being also frequently larger and 

 more robust than the mouth-spines proper. 



Pteeastee, Milller Sf Troschel. 

 Species enumerated. 



P. militaris (0. F. Miill.), Miill. 



& Trosch. 

 P. qffinis, E. A. Smith. 



P. rugatus, n. sp. 

 P. stellifer, n. sp. 

 P. semireticulatus, n. sp. 



Pteeastee militaets (O. F. Miill.), Miill. Sf Trosch. 

 Statioa 49. Lat. 43° 3' N., long. 63° 39' W. Depth 83 fms. ; 

 bottom temperature 1°*8 C. ; gravel, stones. 



Pteeastee, aeeinis, JE. A. Smith. 



Pteraster affims,E. A. Smith, Ann. SfMag. Nat. Hist. (1876), vol. xvii. 

 p. 108; Trails. Venus Exped., Zool. Kerguelen Is. p. 6, pi. xvi. fig. 5. 

 Station 149. Eoyal Sound, Kerguelen Islands. Depth 

 25 fms. 



Pteeastee eugatus, n. sp. 



Marginal contour subpentagoual, interradial angles scarcely in- 

 dented, the lesser radius being in the proportion of 68'4 per cent. ; 

 ^=9'5 millim., r=6'5 niillim. Interradial margin rounded, 

 extremities of the radii slightly upturned, exposing the end of 

 the furrow. Dorsal profile rounded, not high, taperiug but little 

 towards the extremities of the radii. Abactinal surface flat or 

 slightly convex. Lateral fringe very slightly produced beyond 

 the margin of the test. 



Supradorsal membrane subcorrugated, not reticulated. Pax- 

 ill&e-spinelets fine, about 5 or 6 in number ; tips slightly protu- 

 berant, and producing a slight papillate appearance on the dorsal 

 surface ; no regularity of arrangement perceptible. Membrane 

 indurated with minute spicules averaging •03-"04 millim. in 

 length — small, irregular and angularly branching bodies, sub- 



