Boone, Crustacea, Cruises of "Eagle" and "Ara," 1921-28 39 



of setae ; the dactyl is very slender, curved, closing upon the margin 

 of the propodus, claw-like and armed with stiff setae along its outer 

 lateral margin. The second thoracic legs have in addition to the fore- 

 going structure a dense brush of setae across the outer distal margin. 



The third, fourth and fifth thoracic legs are very short, slender, 

 stick-like, reduced, biramous, i.e., having a single lameliform epipod 

 each. 



The abdominal pleopoda but afford no specific characters. 



Synonymy: Squilla alba Bigelow, R. P., Johns Hopkins Univ. Cir- 

 cular, No. 106, p. 103, 1893.— Proc. U. S. Nat. Mus., vol. 17, p. 

 539, 1894. 



Squilla panamensis variety B, Bigelow. 



Plate 6. 



Material examined: Three specimens from Punta Arenas, Costa 

 Rica, March, 1928, taken by the "Ara," William K. Vanderbilt, com- 

 manding. 



Technical description: Rostrum three and one-half millimeters 

 long, three and one-quarter millimeters wide, tongue shape, with the 

 anterior margin evenly rounded. Carapace shield-shape, slightly nar- 

 rowed anteriorly; there is a short, transverse sulcus in the median 

 frontal region behind the rostrum ; the frontal margin on either side 

 of the rostrum is excavate and there is a short, acute, outward and 

 forward directed spine on the anterolateral angle; the anterior two- 

 thirds of the lateral margin is excavate and the remainder is pro- 

 duced into a convex lobe at the postlateral angle ; the median posterior 

 margin is excavate. There are five longitudinal carinae on the cara- 

 pace besides the margins. One of these carinae is median and is in- 

 terrupted posteriorly by the cervical groove, behind which the carina 

 bifurcates, forming a V, The median third of the carapace is sepa- 

 rated from the lateral third on each side by a well-defined groove. 

 The inner lateral longitudinal carina is about one-third the distance 

 between this carina and the outer margin and does not extend quite to 

 the anterior margin; posteriorly it is interrupted by the cervical 

 groove, the hinder portion of the carina curves around the postlateral 

 margin paralleling the margin. The second or outer lateral carina 

 extends from the anterolateral spine almost to the posterior margin. 



The visible thoracic and abdominal segments are transversely con- 

 vex ; the first and second thoracic segments are short, concealed ; the 



