118 CEYLON PEARL OYSTER REPORT. 



Rhyncopora corrugata, n. sp. Plate, fig. 5. 



Zoarium incrusting, yellow-white in colour. Zooecia large, distinct throughout, with 

 the secondary orifice prolonged into a tube, widening from the base up and with an 

 uneven margin. An uncinate process at the base of the tube a little to one side of 

 the centre, and an avicularium of small size on the corresponding other side, its beak 

 pointed and forming with the uncinate process a loop-shaped sinus. 



Locality : Gulf of Manaar. 



The raised secondary orifice of this species gives it the appearance of a Lagenipora, 

 but that the tube is irregularly fluted in outline. It is a good deal smaller than 

 Rliyncop>ora incisor, n. sp., although at first taken to be the same when the two were 

 growing together. 



Rhyncopora incisor, n. sp. Plate, fig. 6. 



Zoarium incrusting, of a white colour. Zooecia crowded, hexagonal, with a deeply 

 areolated margin, a long tubular peristome and even rim. 



Primary orifice orbicular with a transversely placed avicularium a little to one side 

 of the centre, an uncinate process on the opposite side becoming very long and 

 pointed. Ocecia behind the tubular orifice, smooth with a circular area on either side. 



Localities : Gulf of Manaar ; and off Galle, 34 fathoms. 



The chai'acters of this species are very simple and constant ; the most striking 

 feature is the elongated uncinate process which sometimes projects almost across the 

 orifice, so as to bar the entrance to the tube, and has a curved needle-like point. 

 There is no avicularium to be seen when this stage is reached. 



One perfectly preserved colony has the appearance to the naked eye of the pile of 

 white velvet ; the zooecia almost approach those of Lagenipora tuberculata in size and 

 appearance. 



Hippothoa flagellum, Manzoni. 

 Locality : Chilaw Paar. 



Gemellipora glabra, form striatula, Smitt (26). 

 Localities : Gulf of Manaar ; Trincomalee ; and off Mount Lavinia. 



Gemellipora lata (Smitt, 26). 



The Ceylon specimens of this form have the yellow colour of the colony, the dark 

 colour of the opercula, more brown than green in these specimens, the conspicuous 

 pores of the zooecia, the form of orifice and peculiar fold of the peristome below this, 

 as figured by Smitt (26, plate vii., fig. 157). 



Avicularia are distributed among the zooecia, on separate areas, but are much larger 

 than he describes and spatulate, not oval. 



Ocecia, not described before, are more broad than high, perforated like the zooecia, 



