26 CEYLON PEARL OYSTER REPORT. 



Anilocra dimidiata, Bleeker. 



1857, Anilocra dimidiata, Bleeker, 'Acta Soc. >Sci. Iwlo-Neerl., ' vol. 2, art. 5, pp. 30, 31. 

 1881, Anilocra dimidiata, Schiodte and Meinert, ' Nat. Tidsskr.,' ser. 3, vol. 13, p. 103, 111, 



pi. 8 (15), figs. 5, 6. 

 1900, Anilocra dimidiata, Stebbing, in Willey's 'Zoological Results,' pt. 5, p. 639. 



The two specimens obtained agree closely with the description given by Schiodte 

 and Meinert, having, in accordance with their conspectus of the species in this 

 genus, the first antennae geniculate, the coxas not carinate but simple, and the fingers 

 in the first four pairs of trunk -legs inflated in the middle, the inflation here forming 

 a single nodule, not two or three nodules as in A. leptosoma, Bleeker. The 

 colouring also agrees, not merely in being yellow, bespattered with minute dark 

 specks, which is common to so many preserved species, but in the much more peculiar 

 character of being very much darker on the right side of the animal than on the 

 other, in accordance with Bleeker's description. Schiodte and Meinert write as 

 though either side might be the darker. 



The Danish authors speak of their specimens being more or less twisted to the 

 right, whereas ours are quite straight as in Bleeker's figure. They attribute only 

 nine joints to the second antennas, while ours have these appendages ten-jointed. 

 Both first and second antennas, and the latter especially, are much compressed. In 

 one specimen both members of the second pair, and in the other one member, have 

 the antepenultimate joint shorter than either of its neighbours. 



The fifth pleon segment has the postero-lateral angle produced a little over the 

 telsonic segment, which is broader than represented by Schiodte and Meinert, but 

 is, as they describe, obscurely carinate, with raised lateral margins. The peduncle 

 of the uropods is only shortly produced on the inner apex ; the long narrow rami 

 are perfectly smooth, approximately equal in length, the outer a little the narrower. 



One specimen, carrying elongate eggs, measured 24 millims. in length, the other 

 being 22 millims. long. In each case the greatest breadth was 8 millims. 



Locality : Palk Bay, 6 fathoms. 



Rhiothra, Schiodte and Meinert. 

 1884, Rhiothra, Schiodte and Meinert, 'Nat. Tidsskr.,' ser. 3, vol. 14, p. 223, 318. 

 This genus is placed by the Danish authors in the Cymothoinas, the second tribe of 

 their family Cymothoidas. In the somewhat conjectural reference to it of a single 

 specimen, a male not fully grown, it would be out of place to indulge in any long 

 discussion of the characters, for which the original work should be consulted. It may 

 be remarked that the generic definition refers to the female, not to the adolescent 

 male, in which the second antennas have a larger number of joints. 



Rhiothra callipia, Schiodte and Meinert. Plate VI. (A). 

 1884, Rhiothra callipia, Schiodte and Meinert, ' Nat. Tidsskr.,' ser. 3, vol. 14, p. 319, pi. 12, figs. 8-13. 

 The single specimen here available agrees with the account of the " mas adolescens" 



