211 



Body perfectly straight and bilaterally symmetrical as in any macrurous 

 crustacean : the abdominal terga all in contact. 



Carapace about half as long as the abdomen, well calcified dorsally but 

 membranous laterally, the cervical groove well denned. No rostrum. 



Abdominal terga and telson well calcined, as are the fairly well developed 

 pleura of the 2-5 somites. Telson broad, divided into two parts by a transverse 

 suture. Caudal swimmerets quite symmetrical, not so large or long as the 

 telson, well calcified, the outer part of the dorsal surface of both exopodite and 

 endopodite with a pavement of small sharp setose tubercles. 



Ophthalmic scales small, widely separated : eyestalks long, eyes large. 



The upper is much the longer of the two antennular flagella, and is more 

 than half the length of the peduncle. The 2nd joint of the antennal peduncle 

 has its antero-external angle produced to form a serrated spine inside which is 

 a similar but larger spine (acicle). 



The mandibles have a smooth subcircular molar facet lying at right angles 

 with a strong sharp incisor process, and have a three-jointed incurved endopodite 

 (palp). 



The 1st and 2nd maxillae have the coxopodite, basipodite, and endopodite 

 well developed : in the 2nd maxillae the coxopodite and basipodite are deeply 

 cleft and the scaphognathite is posteriorly truncated. 



All 3 pairs of maxillipeds have well developed flagellate exopodites, but 

 none of them except the 1st pair have epipodites, nor are there any epipodites 

 on any of the thoracic legs. The 2nd and 3rd (external) maxillipeds are pedi- 

 form and 7-jointed, the external maxillipeds, which are in contact with one 

 another at base, ending in a nearly perfect chela in which the dactylus is a little 

 longer and slenderer than the fixed finger. 



The thoracic legs of the 1st pair are equal, massive, and symmetrical, 

 having the wrist and hand twisted inwards so that the outer surface of the hand 

 becomes superior : the anterior edge of the carpus is produced as a crest that 

 overhangs the hand, and the hands, which have the palm dorsally flattened, can 

 be jiixtaposed along the whole of their perfectly straight inner edge and can be 

 flexed vertically almost at right angles with the carpus, so as to form an oper- 

 culum to the cavity in which the animal hides itself : the fingers are short with 

 sharp strongly-calcified tips. 



The legs of the 2nd and 3rd pairs are long slender and compressed, and 

 end in elongate curved dactyli : those of the 4th and 5th pairs are short and 

 subchelate, their dactyli being very short and claw-like and a good deal concealed 

 in setae. 



The abdominal appendages of the 1st somite are uniramous in both sexes, 

 ;n id in the male have an almost foliaceous tip: those of the 2nd-5th somites 



