291 



except near the base. They form one of the most characteristic features of the 

 species. 



The zooid-plate is small and inconspicuous, extending hardly one-quarter 

 up the pinnule. It is crescentic in shape and is clearly defined, both the pro- 

 rachidial and the nieta-rachidial origins being almost as long as median radius. 

 The polyps are brown in colour and are clustered mostly on the margin, but a 

 few extend about one-third down the upper surface, on the lower only about 

 one-fourth, thus leaving a distinct space between the polyp-zone and the zooid- 

 plate equal to about one-half of the pinnule. 



The colour is light brown, but there are purple streaks occupying many of 

 the interradial spaces, and there is a large bluish patch on the pro-rachidial 

 surface of the keel. 



Locality : Andamans. 



Pteroeides griseum, Kblliker. 



A single colony of a very remarkable appearance represents this very vari- 

 able species. 



Total length of colony 



105 mm. 



50 mm. 



45 mm. 



60 mm. 



10 mm. 



26 



19-20 



17 mm. 

 8 mm. 



19 mm. 

 15 mm. 



Length of rachis 



Breadth of rachis 



Length of stalk 



Thickness of stalk 



Number of pinnules ..... 



Number of rays ...... 



Length of pro-rachidial margin of largest pinnule 

 Breadth of insertion of largest pinnule 

 Breadth of largest pinnule .... 



Distance between pinnules .... 



The stalk is soft and swollen immediately below the rachis, and from this 

 it tapers to the tip in a .steep cone. The upper half of the meta-rachidial sur- 

 face of the keel is covered by the overlapping pinnules, which are fan-shaped 

 and very broad. The rays are quite soft and flexible, a condition due probably 

 to a pathological variation, seen also in one of the specimens of F. robmtiim, 

 n. sp. In the polyp region on the upper surface of the pinnules there are also 

 numerous needle-shaped bodies of a similar consistency. In other respects this 

 form agrees with Kolliker's P. griseum. 



Locality : Unknown ; No. ^V- (Dr- J- Anderson). 



Previously recorded from Adriatic Sea, Mediterranean Sea. 



