THE WINDOW-PANE OYSTERS. 



43 



20 



188 



162 



Observations. 



Two pearls. 



None. 



None. 



None. 



Several patent white cysts at 

 anterior base of gills (the usual 

 position) each containing a 

 normal parasitic larva sur- 

 rounded by adventitia. 



One pearl. 



A sample for comparison with the above from the same place 

 should be examined towards the end of the year before the next 

 fishery. 



The sand- tubes which adhered to several of the shells were in- 

 habited by Polychaet worms, Eunice indica, all in the same 

 immature condition, about an inch in length (after preservation), 

 the head entire or but slightlj^ notched in front, antennae and cirri 

 smooth, gills commencing on the third foot and ending on the 

 26th-28th feet. 



StationY. — Off the Nachchikkuda (east) shore, opposite to Sinnak- 

 kulam ; depth about one fathom. Many oysters of the statutory 

 size, several slightly below it (5| inches). Ten specimens yielded 

 two hinge pearls and five mantle pearls. 



StationYI. — Before Kakkaimunai, " Crow Point," in one fathom ; 

 collected a sample of a dozen. Nos. 1 and 9 contained a hinge 

 pearl apiece, that from the latter measuring 2 mm. long by nearly 

 1"5 mm. wide. 



This bed might make a good shomng next year ; it corresponds 

 with Mr. Hornell's station 8-8 (1905). Other parts of the Kakkai- 

 munai bed exhibit abundant crops of the sponge called " kadal- 

 palara," referred to by Mr. Hornell, to the almost entire exclusion 

 of placuna. Whether or not it reallj'^ ousts placuna from its position 

 on the beds is a question which could only be answered after repeated 

 observations, the point to decide being whether placuna would settle 

 down where the sponges now reside if it were given the chance. I 

 think it probably would. 



