Dixon — On Sagartia venusta and Sagartia nivca. 119 



It will be seen at once that the above description of Sagartia 

 nivea and Sagartia venusta agrees in the main with Gosse's account 

 of these forms. In three points, however, some difference will be 

 detected in the two accounts. First, in describing the colour of 

 the tentacles, I have mentioned that in both species sometimes the 

 tentacles of the outer row are possessed of an orange core. 1 This 

 is, however, a matter of no great importance. In Sagartia miniata 

 it is by no means uncommon to find individuals without the 

 characteristic cored tentacles, so their occasional presence in S. 

 venusta and S. nivea need not excite surprise. Secondly, in de- 

 scribing the dimensions of S. venusta, I have ventured to differ 

 from Gosse. He (Actin. Brit., pp. 60 and 61) says: "A full-sized 

 specimen, well expanded, is about three-fourths of an inch in 

 diameter of disk ; but the extended tentacles may increase this to 

 an inch and a-half, or rather more. The height rarely exceeds 

 three-fourths of an inch." M. Jourdan agrees with Gosse in 

 making the height and diameter of the column about equal, but 

 the measurement he gives for both, mm , 007, shows that the two 

 specimens on which he bases his description must have been im- 

 mature. In the Irish specimens that I have seen the height was 

 generally twice the diameter of the disk ; and further, the average 

 height was considerably in excess of the limit which Grosse assigns. 

 I have seen many individuals, when expanded, attain a height of 

 two inches, measuring from the base to the margin of the disk ; 

 but I have never seen the disk expanded beyond a diameter of one 

 inch, measuring from margin to margin. Gosse's illustrations of 

 S. venusta (Actin. Brit., PL i., fig. 7 ; Tenby, PL xxiii., figs, a 

 and b, represent shorter and more thick-set specimens than any I 

 have seen. Those which Professor Haddon kindly sent me from 

 Yalentia, as well as those which I found at Dalkey Island, were 

 larger, and more pillar-like. Coupling this with the occurrence 

 of the orange- cored tentacles mentioned above, one is inclined to 

 believe that the S. venusta of our Irish coasts is, perhaps, more 

 robust than its English relations. The proportions of Gosse's 

 illustration of S. nivea (Actin. Brit., PL ii., fig. 8) are very 



1 F. J. Foot (Nat. Hist. Rev., 1860, vol. vii., p. 392) describes a variety of S. nivea 

 with the outer tentacles orange. From the description he gives of the specimen, I am 

 inclined to think that it ought, perhaps, to be referred to S. miniata. 



