Boone, Crustacea, Cruise of "Alva," 1931 119 



Family: ALPHEIDAE 



Genus: ATHANAS Leach 



Athanas djiboutensis Coutiere 



Plate 31 



Type: M. Coiitiere's type was collected in Djibo'.iti, East Af- 

 rica, and is deposited in the Paris Museum. 



Distribution : This species appears to be rather rare, having 

 previously been recorded only four times, but from widely dis- 

 tributed localities: Djibouti, East Africa (Coutiere); Funafuti 

 Atoll, Ellice Islands (Borradaile) ; Rikitea (Nobili) ; Naifuro 

 Reef, Hulule, Male Atoll, Minikoi Island, reefs and lagoons (Cou- 

 tiere) ; Anaho Bay, Nuka Hiva, Marquesas Islands (Boone). 



Material examined : Two specimens, a male and a female, 

 collected in coral reef, at Anaho Bay, Nuka Hiva, Marquesas 

 Islands, August 10, 1931, by the "Alva." 



Technical description : Viewed dorsally, the rostrum is an 

 elongated, acuminate triangle with the apex extending as far as 

 the distal margin of the second peduncular article ; it does not have 

 the obtuse angulation opposite the outer margin of the eye, as 

 shown in Coutiere's figure of the Minikoi specimens. The lateral 

 rostral margin of the present specimen is an uninterrupted ob- 

 lique line ; the supracorneal spine is small, short, separated by a 

 small V-like notch from the rostrum projected forward above 

 the eye for a distance only half so long as the infracorneal spine 

 extends, the latter being closely appressed to the lateral surface 

 of the cornea and extending two-thirds of the corneal length, being 

 slightly shorter than the inferior angulation of the carapace below 

 the orbit, which is seven-eighths as long as the cornea, in this 

 respect agreeing with the profile figure 129b of M. Coutiere, which 

 shows the lower infraorbital angulation to be the longer and larger, 

 which is also true in the present Marquesas Islands specimens. 

 Below the inferior orbital angle the margin slopes gradually to 

 the anterolateral border. The carapace is dorsally quite narrow, 

 much compressed laterally; including the rostrum, it is about 

 two-thirds of the total body length. The abdominal terga are 

 smooth, dorsally rounded, the first, second and third segments sub- 

 equal ; the fourth and fifth segments subequal, but each a little 

 shorter than the third segment ; the sixth segment not quite one 

 and one-half times as long as the fifth ; the telson 1.2 times as long 



