PENNATULIDA OF THE MEEGUI AECHIPELAGO. 275 



Diam. of stalk, average 16 mm. 



Number ofleaves 21 -J-6rud. 



Height of largest leaf 17 



Ventral border of largest leaf 26 



Base of attachment of largest leaf .... 9*5 



Number of rays 19-21 



Length of spines 2 



Pteeoeides Espeei, HerkloU. (Plate XXIII. figs. 12-15.) 



To this form we refer eleven specimens, all from the Mergui 

 Archipelago. They differ a good deal among themselves in colour, 

 and in general appearance and proportions, but we have found it 

 impossible to separate them. 



The general characters agree with those given by Kolliker # , so 

 that there is no need to describe them in detail. Some of the 

 specimens agree in many points with JPteroeides cJiinense, and it 

 is not easy to find reliable differences between the two species. 

 In Pt. Esperi, however, the length of the rachis is greater rela- 

 tively to its width, and the feather is longer relatively to the 

 stalk. The lowermost leaves do not approach so closely on the 

 ventral surface of the rachis, and are not spatulate in form. The 

 leaves are more sickle-shaped, the rays fewer in number, 13-16, 

 and more conspicuous ; the spines are more pointed and slender, 

 and the margins of the leaves more deeply notched between 

 them. 



Our specimens fall into two groups, which we propose to 

 speak of as varieties a and j3. 



Pt. Espeet, var. a. (Plate XXIII. figs. 12, 13.) 



In this variety, of which there are eight specimens, the leaves 

 are markedly sickle-shaped, and the rays very conspicuous on 

 their under surface ; the zooid plate is smaller than in P. chinense, 

 does not extend so far along the ventral border of the leaf, is very 

 slightly dentate at its margin, and is very often brown in colour. 

 The principal measurements of these specimens are as follows, 

 a being a typical one, h and c more extreme forms : — 



* Kolliker, Alcyonarien, pp. 108-113. 



