384 



MR. W. M. TATTERSALL ON THE STOMATOrODA AND 



Tbe four specimens in the present collection have the rostrum armed with 

 seven or eight teeth above, two of. which are on the carapace, and two below. 



Two of tbe specimens still retain tbe second pair of legs, and these, 

 measured, give the following proportions, taking the carpus as unit}'. These 

 measurements are compared with those given by Nobili in his description of 

 this species and with similar measurements taken from Dana's figure and 

 from Borradaile's figure of P. tridentata (1898a, p. 1007, pi. 64. fig. 8). 

 I have addeil the proportions of the joints of the first legs, derived from the 

 same sources. 



Cross! and Red Sea 

 specimens. 



Nobili. 



Dana. 



Borradaile. 

 P. tridentata. 





1st leg. 



2nd leg. 



2nd leg. 



1st leg. 2nd leg. 



1st leg. 



2nd leg. 



•7 

 1-0 

 1-5 



•75 



Merus 



Palm 



1-0 

 1-0 



■4 

 •35 



1-4 1-2 

 10 1-0 

 17 1-6 

 10 10 



1-1 



10 



1-5 



•8 



1-5 1-2 



1-0 10 



•625 1-2 



•625 -8 



•9 



^■0 



•5 



•4 



From this table of measurements it will be noted (1) that in Dana's 

 specimens the palm of tbe second leg is relatively shorter than in either 

 Nobili's specimens or mine, and (2) that my specimens have relativelydonger 

 fingers than either Dana's or Nobili's, though Nobili gives tbe measurements 

 of the palm and fingers of another specimen in which the fingers are 

 relatively longer than in tbe other limb measured and approach more 

 closely to the present specimens. 



As regards the first pair of legs, Dana's specimens have the arm and hand 

 both longer than tbe wrist, while in mine the arm is equal to the wrist and 

 the hand shorter. 



Palcemonella tridentata, Borradaile, is very closely allied to P. tenuipes. 

 Borradaile gives the following points of difference : — 



(1) There are three teeth on the underside of tbe rostrum, instead of two. 



(2) The inner edges of the fingers of the second pair of chela? are armed 



with teeth. 



(3) The distal end of the merus is rounded in profile, but provided with 



a large spine below at a short distance from the end. In P. tenuipes 

 it is acute in profile and without the tooth. 



(4) The arrangement of teeth on the inner ramus of the mandible is 



different in the two species. 



Of these differences, number one is merely an individual variation, and 

 numbers two, three, and four apply also to the present specimens and to 



