146 CEYLON PEARL OYSTER REPORT. 



very minute marginal bulb and two sensory vesicles (sometimes only one), eacb with 

 two small otoliths . 



Size : -Umbrella up to 7 millims. in width and 8 millims. in height. 



Locality : Pearl banks, Gulf of Manaar. 



Notes. The collection contains six specimens, which are mostly about the same 

 size (5 millims. in width and 6 millims. in height) and age. Some are males and 

 others are females having gonads with large ova. The oral lips have an external rib, 

 with an internal groove which is probably ciliated. In this species the gonads are 

 confined to the proximal half of the radial canals, and hang down as laterally 

 compressed sacs. It is upon the position and shape of the gonads that I base the 

 specific character. Excretory pores along the circular canal are not visible. Four 

 of the specimens have 16 radial canals and 16 oral lips, one specimen has 15 canals 

 and another 18 canals. 



JEquorea parva, n. sp. Plate II., figs. 5, 6, 7. 



Description. Umbrella plano-convex in shape, a little broader than high, very 

 thick. Velum of moderate width. Stomach flat and circular, about one-third the 

 diameter of the umbrella. Oral lips 13 to 16 in number, of moderate length and 

 width. Radial canals 13 to 16. Gonads sac-like, in the central third of the radial 

 canals. Four (perhaps eight) tentacles, with large basal bulbs. About 12 or more 

 marginal bulbs between every two tentacles. About 10 or more marginal sensory 

 vesicles between every two tentacles, or usually one between every two bulbs ; each 

 vesicle with two small otoliths. 



Size : Umbrella up to 6 millims. in width and 4 millims. in height. 



Locality : Galle Bay, one on June 5 and two on June 12. 



Notes. The three specimens are about the same size and age. One is a female 

 and the other two are males. The stomach is about 2 millims. in diameter, and its 

 lower wall about 1 millim. in width ; the oral lips do not exceed 1 millim. in length. 

 The gonads have lost their original shape, as they have been crushed down by the 

 folding in of the margin of the umbrella. They occupy the central part of the radial 

 canals, and are slightly nearer to the margin of the umbrella than to the stomach. 

 The gonads hang down as sacs, somewhat laterally compressed. The female has large 

 ova. One specimen has 13 radial canals, gonads and oral lips; the other two have 

 16 radial canals, gonads and lips. Two specimens have only four tentacles, but the 

 third specimen has one interradial bulb which is just developing a tentacle. The 

 interradial bulbs are much larger than the other bulbs and probably have tentacles in 

 a fully developed specimen. The marginal bulbs, which are very variable in size, are 

 somewhat cone-shaped and contain nematocysts. Some of the bulbs have an 

 excretory pore opening on the sub-umbrella just above the velum. One specimen is 

 badly infested with Cercaria. 



