RRACHYURA. 4 1 9 



trout are more or less squarely cut ; (4) the transverse mid-gastric ridge is not 

 continued to the notch between the first and second teeth of the antero-lateral border 

 of the carapace ; (5) there are four ridges on the hand : two of these are ill-defined 

 and unite the two rows of spines on its upper surface a third corresponds in position 

 to the third ridge of var. crenata and is similarly continued on to the fixed finger 

 the fourth is smooth, runs above the third, and ends distally just behind the cleft 

 between the fingers ; (6) there are three spines in the upper row on the palm the 

 distal one is smaller than the other two ; (7) there is a distal spine on the wrist, just 

 behind the upper row of spines of the palm ; (8) the lower border of the propodite 

 of walking leg 4 bears obvious spines distally ; these become smaller proximally and 

 disappear on the proximal third. 



The second specimen is an immature female (CI. = 10) which may probably be 

 correctly put with the above. The fourth tooth of the antero-lateral margin of the 

 carapace is seen under the lens to be excessively minute still more rudimentary than 

 in the male. The ridges of the hand are granular, and there is a trace of an additional 

 ridge above the position of the one which ends interdigitally in the male. 



Remarks on the species Thalamita pryrnna (Herbst). Alcock (1899) supports 

 Kossm ann's view- of the specific identity of T. prymna (Herbst) T. crenata 

 (Latreille) (including T. crassimana, Dana) T. dance, Stimpson T. stimpsoni, 

 A. Milne-Edwards and T. picta, Stimpson i.e., those forms with an eight-lobed 

 front combined with a very broad basal antennal joint. Material recently described 

 tends to justify this view. Thus Calman describes three series of Torres Straits 

 forms (C, p. 22), of which two at least evidently belong to the group, and tend 

 to combine characters of the other members rather than to belong decidedly to any 

 recognised division. The same kind of thing occurs in the specimen of the present 

 collection described above. It is allied by characters (1), (2), and (3) to var. prymna, 

 by (4) to var. crenata and var. dance, while characters (6) and (7) separate it from 

 varieties known to me. Alcogk's key brings the present variety under var. prymna, 

 from which it may readily be distinguished by characters (6) and (7) above. 



Thalamita chaptali, Audouin and Savigjny, 1826 A. 4, p. 80. 



Localities : Pearl banks, Gulf of Manaar, 23 specimens ; coral reefs, Gulf of 

 Manaar, 26 specimens; off Mutwal Island, one specimen; 10 miles north of Cheval, 

 one specimen. 



Description : CI. of an ovigerous female = 8'25. 



Thalamita poissoni, Audouin and Savigny, 1826 A. 4, p. 81. 



Localities : West of Periya Paar, one specimen (ovigerous ? ) ; pearl banks, Gulf 

 of Manaar, one specimen (adult <$). 



Description: CI. of the ovigerous female = 7 '50. 



The fourth tooth of the antero-lateral border is very rudimentary in both examples. 



3 H 2 



