36 ALLAN HANCOCK ATLANTIC EXPEDITION REPORT 



Exposed thoracic somites without carinae; lateral margins of last 

 three thoracic somites subtruncate, slightly concave laterally; inner 

 branch of walking legs ovate on sixth and seventh thoracic somites, that 

 of the eighth somite more elongate. 



Abdomen depressed, loosely articulated, without carinae or spines 

 except at posterolateral angles of sixth somite. 



Telson smooth dorsally, much broader than long, posterior margin 

 forming a false eave overhanging true posterior spines; false eave with 

 a broad median projection slightly swollen dorsally, flanked on either 

 side by a sinuous, shallow depression ; margin, lateral to depressions, 

 slightly sinuous; apices of submedian denticles and marginal teeth 

 visible dorsally ; posterior armature, on either side, consisting of five 

 to eight fixed submedian denticles, a large, movable spine, anterior to 

 the outermost denticle, and five to eight fixed spines, in an irregular 

 row, lateral to the outermost denticle. 



Uropodal outer branch with 5 graded, movable, spatulate spines on 

 outer margin of penultimate segment, the last spine extending past the 

 midpoint of the ultimate segment; inner distal margin of penultimate 

 segment of outer branch with two to four slender, movable spines; 

 outer spine of basal prolongation slightly longer than inner. 



Discussion : The material from the Virgin Islands was included in 

 this account so that some idea of the variation in this species could be 

 obtained. The additional material strengthens the validity of both this 

 species and L. hancocki, which is based on a single specimen. 



The raptorial claws are present on only two of the Virgin Islands 

 specimens ; each claw is armed with seven teeth, as opposed to eight in 

 the holotype. The number of submedian denticles in the Virgin Islands 

 material varies from 10-16, usually 13; there are 15 on the Venezuela 

 specimen. Finally, the Venezuela specimen has but 7 fixed spines lateral 

 to the submedian denticles, while there are 5-7 in the paratypes. 



L. antillensis differs from L. grayi and L. hancocki in that the antero- 

 lateral angles of the rostral plate are more acute; there are fewer den- 

 ticles in the submarginal row of the telson than in L. hancocki, although 

 the count overlaps for L. grayi (15-18) and the present species. The 

 submedian emarginations of the false eave of the telson are much more 

 pronounced in this species than in L. grayi; they are more pronounced 

 in L. hancocki than in L. antillensis. 



L. antillensis can be separated from both L. decemspinosa and L. 

 chilensis by the subquadrate form of the rostral plate, the smaller num- 



