Dixon — On Sagartia venusta and Sagartia nivea. 121 



have only one groove, while only one S. venusta expanded suffi- 

 ciently to let me examine its mouth and oesophagus, and it had 

 two oesophageal grooves. I examined carefully seven of the speci- 

 mens of S. miniata, and of these four had two grooves, and three 

 one groove. In all these species great care must be exercised in 

 examining the mouth when counting the number of the grooves, 

 for the lip is so frequently thrown into lobes and puckers, that if 

 it alone be examined it will be very likely to mislead, and a 

 cursory observation might even induce one to believe there were 

 three or more grooves. But when, as is frequently the case in 

 all three species, the mouth gapes, or the oesophagus is protruded, 

 we can easily discover the position of the grooves, and recognize 

 their number. I feel sure that the fact that there is sometimes 

 only one groove present in the oesophagus in these three Actiniae 

 has escaped notice hitherto, owing to the varying and irregular 

 configuration of the mouth. 



As to the cinclides, I have been able to satisfy myself of 'their 

 existence in all three forms — Sagartia nivea, S. venusta, and S. 

 miniata. Gosse's account of these openings (Actin. Brit., pp. xxv- 

 xxix) is, I believe, quite accurate. In one point only I have not 

 been able to verify his observations — that is, I have never seen the 

 cinclides overspread by a film of mucous such as he describes. In 

 each of the three species just mentioned, when the animal is fully 

 expanded, there generally may be seen, on the upper third of its 

 column, fifty to one hundred open cinclides arranged in three 

 encircling belts, each cinclis being invariably situated midway 

 between two of the longitudinal lines which mark the column, and 

 therefore probably communicating with one of the spaces between 

 the mesenteries. When open, these pores seem to be surrounded 

 by a ring of tissue, more densely coloured than the adjoining region. 

 In Sagartia miniata the warmer and richer colour of the column 

 renders this densely-coloured ring and the cinclides more con- 

 spicuous than they are in S. nivea and S. venusta. Perhaps I 

 should state that I have never observed the cinclides " anatomically 

 by transverse and horizontal sections," and that for the account I 

 have just given of them I am indebted entirely to " observation 

 with the naked eye." My reason for having thus gone at length 

 into the appearance presented in the living animal by these minute 

 pores is to be found in the way Professor E. Hertwig has seen fit 



