310 Records of the Indian Museum. [Vol XXII, 



in one from the Persian Gulf the inner margin of the inner uropod 

 was devoid of setae_ in this resembling Henderson's original 

 figure, whereas in all the other specimens the inner margin was 

 invested with setae. 



Tattersall has recently remarked that it is "just possible" 

 that Bigelow's sbinosiis may be constantly differentiated from the 

 typical foim by the presence of setae on this margin and, on re- 

 examiiling all the material at our disposal, we are inclined to 

 agree with him. We find, however, that no precise correlation 

 exists between the degree of spinulation of the telson, the size of 

 its lateral teeth and the presence or absence of the fringe of setae. 

 All that can be said is that in specimens which possess the fringe 

 of setae, the telson has a moderate to large number of spinules, 

 which are usually small, while the lateral teeth of the margin are 

 frequently reduced and sometimes absent. In specimens in which 

 the fringe is absent the spinules are usually larger and few to 

 moderate in number, white the lateral teeth are nearly always 

 well developed. 



In the material we have examined the setae on the inner 

 margin of the inner uropod are either present or absent : interme- 

 diate forms do not occur. The character thus appears to be more 

 useful for the distinction of a varietal form than the shape of the 

 telson and the extent to which it is covered by spinules, for in 

 both these respects there is a very great range of variation. 

 Bigelow, however, does not refer to the inner uropod in his 

 description of G. spinosus and until we are certain that the inner 

 edge bears setae in his type specimens, it is impossible to say 

 whether the new character can legitimately be employed for the 

 separation of a variety under that name. 



We consider that a variety, which may at present be termed 

 var. spinosus ? , should be separated from the typical form on the 

 basis of the character of the inner uropod and, if this be done, 

 a number of the specimens recorded in 1913 a'; typical G. demani 

 must be referred to the variety. Including the additional ex- 

 amples listed below, the distribution of the two forms as repre- 

 sented in the collection, is as follows : — 



Typical form, — with inner margin of inner uropod devoid of 

 setae, — Gulf of Suez, Persian Gulf, northern end of Gulf of 

 Manaar, Madras Harbour. 



Var. spinosus ?, — with inner margin of inner uropod ])rovided 

 with setae, — Portuguese E Africa, Persian Gulf, Karachi, 

 Bombay, Gulf of Manaar (Pearl banks). 



It will be noticed that both forms occur in the Persian Gulf 

 and Gulf of Manaar and Tattersall has shown that l)Oth also 

 occur in the Red sea. 



Additional specimens are from the following localities : — 



C. 3.37/1. Tor, Gulf ol Suez, Red Sea. R. B. S. Sewell. 1-^,89, 21-.13 



mm. 

 C 338/1. Ain Musa, Gulf of Suez, Red Sea. ,, i3,2g\nm. 



C 339/1. Madras Harljour, 4-5 fms. S. Kemp. 2 c^ , i 9, iS-27 mm. 



