358 CEYLON PEARL OYSTER REPORT. 



of the fixed finger. The horizontal upper surface of the hand meets the oblique 

 antero-inner surface at an angle, forming an oblique ridge crowned by a characteristic 

 row of enlarged granules (six in this specimen). The inner surfaces of hand and 

 fingers form together a hollowed area. The fixed finger is not constricted off from 

 the hand and is much more massive than the dactylus. The upper surface of the 

 dactylus is fluted three granular ridges defining two grooves. There are two 

 longitudinal rows of granules on the fixed finger. The distal two-thirds of the 

 apposed border of either finger is flattened to form a facet which is bordered by a few 

 very sharp denticles ; the tip of each finger forms a curved tooth that of the dactylus 

 closes to the inner side of that of the fixed finger. 



The meropodites of walking legs 2, 3, and 4 are concealed by the carapace ; the 

 succeeding three segments are short, so that by folding the legs at the joint between 

 meropodite and carpopodite they may be entirely concealed from dorsal view. [The 

 first walking legs are lost.] The basipodites and the three distal segments are 

 granular. The meropodites are trigonal, their borders tend to be granular, and their 

 surfaces smooth (obsolescently granular under lens) the proximal one-third of the 

 under surface occupies a different plane from the distal two-thirds, and is granular. 



Remarks. The new species is closely related to Tlos petrceus, A. MILNE-EDWARDS, 

 1874 (A.2, p. 176), but may be easily distinguished from it by the unbroken character 

 of the oblique post-cardiac ridges. It differs further from T. petrceus in the following 

 particulars: (1) The front is more produced and more upturned; (2) the true 

 posterior border of the carapace does not project further backward than the lobe on 

 either side of it ; (3) there are two marginal sutures only on each side ; (4) there 

 is a stronger contrast between the obsolescent granules of the general surface and 

 the enlarged granules of special areas; (5) in the prominence of the pterygostomian 

 region ; (6) the orbits are less ventral ; (7) sculpture of cheliped in particular the 

 presence of the oblique row of granules on the upper surface of the hand ; (8) the 

 facets on the apposed borders of the fingers. 



Tlos latus, BORRADAILE, 1903 (B.VL, p. 437), differs in (1) Absence of marginal 

 sutures of carapace ; (2) absence of oblique line of granules on upper surface of hand ; 

 and (3) isolation of lateral cardiac hump. 



Lithadia sculpta, HASWELL, var. aglypha, nov. Text-fig. 2. 







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



Description: An immature individual. C.I. = 8*5. 



It bears a considerable general resemblance to the already described form of 

 L. sculpta, but differs from it in the following particulars : (1) The carapace is 

 broader in proportion to its length C.b. -r-C.l. = 1*26; (2) the two grooves which 

 border the cardiac region laterally are not continued forward until they meet, but 

 terminate apart in the middle region of the carapace ; (3) there is a mere trace of an 

 iutestino-cardiac groove, quite different from the well-cut channels which the other 



