fiS 



CEYLON PEARL OYSTER REPORT. 



oyster "spat." The Alga was growing on what the divers call "flat rock" a 

 calcrete formed by the- cementing together of the sand and shell fragments in situ. 

 We also obtained at the same spot a fine tnberenlated dark green Holothnrian 

 (Stichopus chloronotus). 



In the afternoon we dredged to the north of the East Ctaeval Paar, running a line 

 of hauls to the Vankali reef lying about 6 miles to the north and then north-west 

 alone- the outer face of the reef and so back. Six hauls were taken which may be 

 united as 



STATION LIL Between north of Cheval Paar and Vankali reef; depth 3 to 6 

 fathoms ; bottom sand ; no pearl oysters ; dredged. 



Ilalicornaria setosa and 77. saccarla, Lytocarpus (( n. sp.) and Sertularia tenuis, 

 Cavernularia obesa (many), Virgularia juncea ; 



Hermadion sp., Panthalis melanonotus, Psammolycc sp., Onuphis sp. ; 



Ostracod (very large, possibly Cypridina forrnosa, or a new form) ; Modiula sp. (in 

 gelatinous nests), and other Lamellibranchs, Turbinella pyrum, Strombus succinctus, 

 Pinaxia coronata, Pyrazus palustris, Persona ridens and Bucdnum melanostoma, ; 



A sum met ran (Heteropleuron) cultellum. 



The Tow-Nets at this locality gave us about 28 species of Copepoda, representing 

 12 genera. These like the other tow-net results will be given in detail in the report 

 on the Copepoda, but Messrs. Thompson and Scott give the following as noteworthy 

 from this haul: Mecynocera clausi, Paracalanus parvus, Acrocalanus longicornis, 

 Centroparjes furcatus and a new species, Pseudodiaptomus aurivittii, Labidocera 

 pavo, L. kroyeri and a new species. 



During parts of this day we had living pearl-oyster spat under observation in fiat 

 wooden tanks and in our narrow vertical " window" aquaria. In the latter, numbers 



S> 



V 



B. 



Fig. 10. Arrangement of spat on glass of aquarium 7 minutes after all started from bottom. 

 B, one individual enlarged, showing the extended foot. 



of individuals placed at the bottom started at once to climb up the glass sides and 

 travelled on the average at the rate of about an inch per minute. At the end of the 



