Collected by the late Dr. J. I. Northrop. 189 



ing 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 number 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 col- 

 lected by Dr. E. A. Andrews at Green Turtle Bay, Bahama Is- 

 lands. 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 identitj^ with Lesueur's M. nymphcea, 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 coloration and base the identification with nympheea, rather 

 than with auricula, on the number of tentacles, which is about 

 fift}'', 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 pre- 

 served specimens a height of about 2.0-3.5 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 capitulum shows clearly a num- 

 ber of radiating ridges. 



The column wall is smooth and without imbedded particles of 

 foreign matter. In structure it resembles closely what has been 

 described for Zoanthus sociatus, the same large lacunar spaces oc- 

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

 outermost portion of the mesogloea, being covered by a meso- 

 gloea, subcuticula and by a cuticle, much more distinct in some 

 specimens than in others. The sphincter muscles, which, for 

 diagnostic purposes, seem to be of great importance in the 

 Zoanthe8e,is double, the two parts being well marked oflTfrom one 

 another. The arrangement is shown in fig. 5, and from this it 

 will be seen that the upper portion of the sphincter is small, while 



