British Species allied thereto. 479 



are a little swollen and puffed near the base and the reduction 

 of the dorsal spines is not so marked. It is very probable 

 that this, if a " new species," is one not only in the corre- 

 sponding French sense of " inedit," but even in the evolu- 

 tionary sense of the word. 



We appear to be justified in regarding this species as 

 distinct on account of the constancy of its slate-grey or violet 

 colour, its flat arms, more slender than in A. ruhens (except 

 the variety attenuata, in which the rounded arm-form of A. 

 ruhens is retained), its loss of dorsal spines, and its limited 

 geographical range. 



I am not acquainted with any additions that have been 

 made to our knowledge of tlie characters of A. Msinda since 

 1881, when I published (Proc. Zool. Soc. Lond.) what infor- 

 mation and criticism I could get together on the species. 



It was then found that E, may be no more than twice r, 

 that the adambulacral spinulation is constantly monacanthid, 

 and that the major pedicellariaj are absent. The combination 

 of these three characters may well be regarded as diagnostic 

 of a species, and such forms as present it may be called A. 

 Mspida, 



EXPLANATION OF THE PLATES. 

 Plate XIV. 



Figures to illustrate some of the variations in spinulation seen on the 

 back of Aster ias rubens. 



Fig. 1. Spines rather blunt, thickly scattered over the whole surface. 



From Aberdeen. 

 Fig. 2. Spines blunt, with flat or rounded, not sharp tips, not at all unlike 



fig. 4. From Tenby, low water. 

 Fig. 3. Blunt spines, more reduced than in fig. 2. South-west Ireland. 

 Fig. 4. A specimen sent by Dr. Norman as an example of A, violacea ; 



compare with fig. 2. From Seaham. 

 Fig. 5. Spines more reduced than in fig. 3, but of the same type. From 



CuUercoats. 

 Fig. 6. Spines larger than in fig. o, but rarer, sharp at their tips. From 



Plymouth. 

 Fig. 7. Spines much sharper, rather stronger and rather less numerous 



than in an ordinary A. ruhens. From Aberdeen. 

 Fig. 8. Of the same character as fig. 7, but more pronounced; spines a 



good deal stronger than usual. Frcmi Shetland. 

 Fig. 9. A very finely developed specimen from Kilbrennan Sound. 



All of the natural size. 



Plate XV. 

 Fig. 1. Astenas Murrayi, natural size. Figure to show the general habit 



of this starfish, its flat arms constricted at their base, and the 



rare scattered spines. 

 Fig. 2. Part of upper surface of arm, natural size. 

 Fig, 3. Part of lower surface of arm, natural size. 



