297 



pro-rauhidial and the meta-racliidial surfaces of the keel are free throughout 

 their entire length. 



The pinnules are narrow and sickle-shaped. The zooid-plate is broad on 

 the pro-rachidial surface ; from this it arches towards the meta-rachidial insertion, 

 tapering almost to a ])oint, but it can hardly be called small as in P. manillense, 

 Kolliker. It is visible to the naked eye. 



The rays of the pinnules are very conspicuous and are comjjosed of about 

 five spines abreast in some places. The polyps occur in four to five rows on 

 both sides of the pinnules, extending on the lower side almost to the zooid- 

 plate. They project mai'kedly beyond the margin which has a serrated ap- 

 pearance. There are a number of superior zooids on the pinnules and 

 abundant limy needles in the polyp region. 



The following table contrasts this species with P. pellucidum and P. 

 manilleme : — 



The colour is creamy- white, but the stalk and rachis are studded with bluish 

 spots which are also seen in the pinnules. 



Locality : Near Palk Strait, 7 fathoms. Marine Survey. 



Pteroeides flavidum, Kolliker. 



A single specimen of a cream-white colour with the following measure- 

 ments ; — 



Total length of colony 95 mm. 



Length of rachis . 



38 



Breadth of rachis . 

 Length of stalk 

 Thickness of stalk . 

 Number of pinnules 

 Number of rays 



50 mm. 

 50 mm. 

 45 mm. 

 17 mm. 

 26 

 18-22 



