234 Capt. A. C. MacGilcbrist on Decapod Crustacea 



to say, they -^ere caiiglit in abundance on two occasions in 

 the Gulf c£ ]\Iartaban, 40 and 61 fatlioms. In one haul 

 fiitecn males and seven females were obtained. 



They agree iu all details witb Spence Bate's description. 

 In tbelndian variety the rostrum is long, horizontal, slightly 

 turned up at the tip, and armed dorsally with 6 (sometimes 5) 

 teetb ; it is half (or more) the lengtb of the carapace, longer 

 in the female, where it is H-2 mm. more than half the 

 lengtb of the carapace, and is about twice the length of the 

 eye. 



* The antennules of the female are shorter and more slender 

 (both peduncles and flagella) than those of the male, and in 

 con^^cquence the antennal scale, which in the male is shorter 

 than the antennular peduncle, is in the female considerably 

 longer than the j)eduncle. 



The antenna is about 1^ times the length of the body 

 (excluding the rostrum). 



Two typical si)ceimens of female and male give the 

 following measurements : — 



Female. Male, 



mm. mm. 



Length cf body, excluding rostrum .... 68 7."> 



„ rostiiim 12 12 



„ anterna S9 1C6 



„ smaller antennular flagellum . G^ ]8^ 



„ larger „ „ .11 24 



„ canipace 19 21 



On analysis and comparison of about two dozen specimens 

 the following .sexual differences are apparent : — 



Ftmale. — Rostrum about twice the length of the eye and 

 11-2^ mm. longer than half the length of the carapace : 

 antennular peduncle considerably shorter than the antennal 

 scale; its larger flagellum very slightly longer than half the 

 length of the carapace, and its smaller flagellum about two 

 thirds the length of the larger. 



Male. — Rostrum seldom twice the length of the eye and 

 about half the length of the carapace : antennular peduncle 

 ])rojects beyond the antennal scale; its smaller flagellum is 

 very little shorter than the cara])ace, and the larger flagellum 

 is a third as large again as the smaller. 



Roughly speaking, the smaller flagellum of an adult male 

 is about three tim.es the length of that of a female. The 

 small younn male rcf^cmbles the female as regards the rclati\e 

 lengths of antennal scale and antennular peduncle and 

 flagella. 



