128 CEYLON PEARL OYSTER REPORT. 



Lang's monograph I can find no further records, save of Cestoplana ceylanica added 

 by myself.* 



Three of the species described below were collected in Ceylon by Mr. Gardiner in 

 1899. He has been good enough to permit me to incorporate my account of them 

 with that of the species with which Professor Herdman has kindly entrusted me. 



Paraplanocera aurora, Laidlaw. 



Paraplanocera aurora, Laidlaw, 'P.Z.S.,' 1903, vol. II., Part I., p. 102, Plate IX., fig. 1. 

 One specimen which agrees in every respect with the type specimen from Zanzibar, 

 save that it is nearly twice as large, being about 30 millims. in length, whilst 

 Mr. Crossland's specimen was only 15 millims. long. The Ceylon specimen was 

 found at Station XVI. , on the Periya Paar, in the Gulf of Manaar, at a depth of 

 y fathoms. 



Woodworthia, n. gen. 



Closely allied to Idioplana. Body rounded, no notch on the anterior margin. A 

 complete series of marginal eye-spots present. Prostate provided with a duct 

 which joins the vesicular duct at the base of the penis. Female aperture separated 

 from male ; vagina of great length, having a bilaterally symmetrical accessory vesicle. 



Woodworthia insignis, n. sp. Plate, figs. 1 and 9. 



One specimen, pearl banks, Gulf of Manaar. 



Measurement*. Length, about 25 millims. ; breadth, about 22 millims. Buccal 

 opening sub-median. Male aperture about 4 millims. from hind end of body ; female 

 aperture about 0'5 millim. behind male. Tentacles 5 millims. apart. 



Coloration. In the spirit specimen an uniform whitish brown, in the living 

 creature probably white. Scattered irregularly over the whole dorsal surface are 

 numerous minute black dots of pigment. 



Eye-spots. These are grouped in a dense cluster at the foot of each tentacle, over 

 the brain, and round the margin of the body. The spots over the brain are few in 

 number and rather widely scattered. Those on the margin are very minute and are 

 irregularly arranged ; on the front part of the margin they may be two or three 

 rows deep. 



Body-wall. The epidermis, both on the ventral and on the dorsal sides, contains 

 numerous long, rather slender rhabdites, those on the dorsal side being nearly half as 

 long again as those on the ventral side. 



The basement membrane is remarkably thick. The muscles of the body-wall 

 consist on the dorsal side of a longitudinal layer next the basement membrane, 

 followed by diagonal fibres, and on their inner side a circular layer. On the ventral 



* Laidlaw, in Gardiner's 'Fauna and Geography of the Maldive and Laceadive Archipelagoes,' vol. I., 

 Part III., p. 302, fig. 72. 



