ACTINIANS FROM THE BAHAMA ISLANDS 111 



can be associated with Lesueur's type species, and it is interesting 

 accordingly to have an account of the structure of one of Lesueur's 

 species, in order that the true position of his genus may be determined. 



Among the slides which Dr. Northrop had prepared I find a 

 number of a Zoanthid which he had provisionally designated No. 3, 

 and also a niunber of drawings of the same form, one of which was the 

 figure of the group of individuals taken from preserved specimens 

 (fig. 4). Unfortunately, in the material forwarded me there were no 

 examples of this No. 3, but there were specimens of a form which the 

 accompanying label stated to have been collected by Dr. E. A. An- 

 drews at Green Turtle Cay, Bahama Islands. This form resembled in 

 general appearance the drawing of No. 3, and preparations which I 

 made of it demonstrated with certainty its identity with Dr. Northrop's 

 No. 3. 



As regards its identity with Lesueur's M. nymphaa, there must 

 necessarily be a certain amount of uncertainty. It agrees with the 

 figure of M. auricula given in Lesueur's paper, and it answers the 

 generic description ; unfortunately, I find no memoranda of its colora- 

 tion, and base the identification with nymphaa, rather than with auri- 

 cula, on the number of tentacles, which is about fifty, and which 

 Lesueur states to be about fifty in the former species and from twenty- 

 six to thirty in the latter. 



The individual polyps composing a colony are seated close together 

 upon a coenenchymatous expansion, and reach in preserved specimens 

 a height of about 2-3.5 mm., the measurement being taken from the 

 point of attachment to the coenenchyme. The diameter of the column 

 is about 3 or 4 mm. at the top, slightly less lower down, and the capitu- 

 lum shows clearly a number of radiating ridges. 



The column wall is smooth and without embedded particles of 

 foreign matter. In structure it resembles closely what has been 

 described ior Zoanthus sociatus, the same large lacunar spaces occurring 

 in the mesogloea, while the ectoderm is enclosed within the outermost 

 portion of the mesogloea, being covered by a mesoglceal subcuticula, 

 and by a cuticle, much more distinct in some specimens than in others. 

 The sphincter muscle, which, for diagnostic purposes seems to be of 

 great importance in the Zoantheae, is double, the two parts being well 

 marked off from one another. The arrangement is shown in fig. 5, 

 and from this it will be seen that the upper portion of the sphincter is 



