9,76 CEYLON PEAEL OYSTKK EEPOPT. 



middle; shell smooth, white, with numerous whiter spots on its surface; size, 

 0'6 millim. 



In general washings from the Gulf of Manaar. 



The species resembles Xestolebris variegata, but is much more tumid. 



Paracytheridea perplexa, n. sp. Plate L, figs. 26 and 27. 



Shell seen from the side subrhomboidal, two and a half times longer than broad ; 

 anterior extremity obliquely rounded, with three median teeth ; posterior produced 

 into a median triangular beak ; dorsal margin highest in front, sloping downwards 

 towards the posterior in an irregularly sinuous line ; ventral margin slightly convex 

 in front, rising with a gentle slope posteriorly, deeply notched at the hinder end, and 

 then suddenly produced into a curved triangular tooth-like process ; seen from above 

 the outline is much like that of a Trilobite, very wide and rounded in front ; narrowing 

 slightly posteriorly, then rapidly converging to form a wide triangular end ; greatest 

 width much in front of the middle, and equal to three-fourths of the length ; surface 

 of the shell marked with large puncta, and in side view with obliquely transverse 

 ridges; size, 0'65 millim. 



A few specimens in the general washings from dredged invertebrates from Gulf of 

 Manaar. 



The species resembles Paracytheridea depressa, G. W. Muller, but differs in the 

 termination of the lateral margins as seen from above. In P. depressa the margins 

 end in a distinct tooth projecting at nearly right angles to the sides. 



Cytherura concinna, n. sp.- Plate II., figs. 7 and 8. 



Shell seen from the side subrhomboidal, with a well-marked dorsal ridge, height 

 equal to half the length ; anterior extremity obliquely rounded, posterior broadly 

 beaked above the middle ; dorsal margin rugged, broken by a few small blunt 

 projections, sloping gently upwards towards the posterior, ventral convex in the 

 middle ; seen from above broadly triangular, greatest width much behind the middle 

 and equal to two-thirds of the length ; anterior extremity rounded and produced into 

 a blunt median beak; posterior very wide, subtruncate, and produced into a large 

 median process, its margin forming a distinct rlexuous ridge coursing between the 

 outer and inner margins of each valve ; surface of the shell marked with numerous 

 puncta, and with a distinct depression in the centre of each valve; size, 0"53 millim. 



One or two specimens in general washings from dredged invertebrates from Gulf of 

 Manaar. 



Loxoconcha anomala, Brady. 



In general washings, in washings from Cheval pearl oysters, and in a dredging 

 from Karativo Paar. 



