134 CEYLON PEARL OYSTEE REPORT. 



isolated clusters upon the manubrium. Four tentacles with globular basal bulbs, and 

 with numerous small clusters of nematocysts. Ocellus upon the outer side of each 

 basal bulb. 



Size : Umbrella about 3 millims. in width and height. 



Locality : Galle Bay, one specimen on June 12 and two on August 25. 



Notes. The umbrella of the three specimens is so badly out of shape that a figure 

 of it cannot be given. The manubrium (fig. 2) is a long thin tube, about two to 

 three times the length of the cavity of the umbrella, with an apical knob in the jelly 

 of the umbrella, and with a large terminal stomach which has a circular mouth. The 

 gonads are situated on the manubrium in large roundish clusters, and their size makes 

 them conspicuous. One specimen has four clusters of gonads, another has two 

 clusters. The third specimen has lost its manubrium. The stomach itself also 

 appears to be surrounded with generative cells. The tentacles (fig. 1) are long and 

 flexible, and are closely studded with clusters of nematocysts, except for a short 

 distance next to the basal bulb. The upper half of the basal bulb is globular and 

 embedded in the jelly of the umbrella, the lower part is like a circular band round 

 the tentacle, broader on the inner side than on the outer side. In this band, on the 

 outer side, the ocellus is situated. The ocellus is circular, of a yellowish colour in 

 formalin, and has a small lens. 



I have placed this species in the genus Dipurena and follow at present Haeckel's 

 classification, though 1 think that this species and Dipurena ophiogaster will 

 ultimately have to be removed to another genus. All the other species have the 

 nematocysts on the tentacles confined to a large conspicuous terminal knob, and some 

 in addition have a few large swellings containing nematocysts just above the terminal 

 knob. Dipurena ophiogaster has the nematocysts on the tentacles arranged in quite 

 a different manner. They form numerous semi-circular or three-quarter spiral loops 

 round the tentacle when it is in a contracted or semi-contracted state. When the 

 tentacle is fully expanded the nematocysts form minute globular clusters which give 

 a moniliform appearance to the tentacle. The terminal cluster of nematocysts is very 

 small and inconspicuous. The arrangement of the nematocysts of this species from 

 Ceylon is similar to that of Dipurena ophiogaster and to that found in the genus 

 Sarsia. 



The specimens from Ceylon are very much like Dipurena ophiogaster which belongs 

 to the British fauna, and it is not possible to point out a character in the structure of 

 the tentacles or the manubrium with its gonads by which they can be specifically 

 separated. As the specimens are in bad condition, 1 think it is best to leave the 

 specific name in abeyance. They may differ from the Dipurena ophiogaster in the 

 shape of the umbrella, in colour, and perhaps in other details. 



Bigelow (1904) found at the Maldives a Dipurena which he was not able to 

 clearly distinguish from Dipurena frugilis, Mayer, belonging to the fauna of the 

 Tortugas in the West Indies. 



