MACKUROUS DECAPODA OF THE SUDANESE RED SEA. 375 



times as long- as wide. The telson is not spinous at the lateral corners of 

 the apex. The species seems to me to be very closely allied to S. tricus- 

 mdatus of Heller. 



Distribution. New to the fauna of the Red Sea. Only recorded by 

 Coutiere from the Maldives. 



Biunguiculatus group. 



Synalpheus biunguiculatus (Stimpson) Coutiere. 



S. biunyuiculatus, Coutiere, 1905, p. 873, pi. 71. fig. 8. 

 <S'. biunyuiculatus, De Man, 1911 b, p. 273, pi. 11. fig. 51. 



Localities. Station V. B, one broken. Station V. A, one, 10 mm. Station 

 V. C, 1 £ , 12 mm., and 1 ? , 15 mm. Station X., 1 ? , 15 mm. 



Remarks. All these specimens belong to the typical form of the species as 

 defined by De Man. 



Distribution. Previously recorded from the Red Sea by Coutiere, from 

 Suez and Djibouti ; Maldives and Laccadives (^Coutiere) ; Dutch East 

 Indies (De Man). 



Nobili has recorded this species from Massaouah in the Red Sea. hut 

 De Man states that it is not possible to say what species he had under 

 observation. 



Synalpheus savignyi (Guerin), 1856, pp. 47-51, pi. 2. figs. 8-11. 



Athanas nitescens, Audouin & Savigny, 1826, p. 90, pi. 9. fig. 4. See also Coutiere, 

 1899, p. 17. 



Locality. Station I. F, 1 $ , 15 mm. 



Remarks. I have not been able to consult Guerin's works, and I am 

 indebted for the reference thereto to Coutiere. The single specimen at my 

 disposal agrees absolutely with Savigny's figure, and I have little doubt 

 that it belongs to the species which Savigny had under observation and, 

 moreover, it seems to me that Savigny's figure is an extraordinarily faithful 

 reproduction of the species. S. savignyi is very nearly allied to S. biungui- 

 culatus, and before I was able to consult Savigny's work I had noted it. as a 

 variety. The rostrum is exactly as figured by Coutiere for S. biunguiculatus 

 except that the left tootli of the trident is almost obsolete. The carpocerite 

 is slightly longer than the antennular peduncle, while the scaphocerite is 

 equal in length to the latter. The antennal scale reaches forward to the 

 distal end of the second joint of the antennular peduncle. The inferior 

 spine of the basicerite is equal to the stylocerite, while the superior spine of 

 the basicerite is quite well developed. 



The outstanding feature of the species is to be found in the palm of the 



