480 CEYLON PEARL OYSTER REPORT. 



1. Carapace covered by numerous often more or less squami- 



form tubercles, each bordered by a fringe of short stiff 

 hairs : 



a. Posterior coxal process of 2nd and 3rd walking 



legs entire var. tuberculoid. 



b. Posterior coxal process of 2nd and 3rd walking 



legs dentate var. depressa. 



2. Carapace tubercles more depressed those on gastric region 



obsolescent : 



a. Posterior coxal process of 2nd and 3rd walking 



legs entire var. immaculata. 



The few specimens hitherto described show that the above distinctions are average, 

 not absolute, e.g., Miers' " Challenger" specimen of depressa is hardly dentate, and 

 dk Man describes an example of immaculata which has a few hairs on some tubercles. 

 The amount of material is not sufficient to enable one to estimate the exact degree of 

 overlapping. 



Additional differentia requiring investigation are : 



1. Miers points out that carapace is more convex in immaculata than in depressa, 

 or tuberculata. This holds in general, but is broken in two instances known to me 

 among the collections of the British Museum, in which tuberculata shows approximately 

 same degree of convexity as immaculata. 



2. Degree of fusion of abdominal terga 3, 4, 5 and 6. I have before me only 

 4 males (l immaculata + 2 depressa + 1 tuberculata), which suggest that the tendency 

 for such fusion may be found to be greater in depressa and immaculata than in 

 tuberculata. 



3. Shape of abdomen. 



4. Size of carapace immaculata being smaller than the others. 



Of the above, the first at least is of value possibly all are so. I retain for the 

 varieties the names used by Miers, entirely avoiding squamosa. If used, the latter 

 should apply to the tuberculata series only, but it has the grave disadvantage of 

 having been used by Herbst to denote in the text a form with entire coxal process, 

 and in his figure one with coxal process dentate. 



Palicus jukesi (White, 1847)^A.6, p. 451 Plate I., fig. 12. 



Locality : Coral reefs, Gulf of Manaar, one specimen. 



Description: An adult male. C.l. = 14 - 25 (frontal lobes included). C.b. -j-C.l. = 1*11. 



Remarks. This specimen confirms Calman's inclusion of Cymopolia carinipes, 

 Paulson, 1875, in the synonymy of the species for, while answering to Alcock's 

 description, it has, instead of the sub-hepatic tubercle described by Calman for his 



