ARTHROPODA. 849 



Family THALASSINIDAB. 



Genus Callianassa Leach. 



Callianassa mortoni Pilsbry. 



Plate CXI., Figs. i-is. 



1901. Callianassa mortoni Pilsbry, Proc. Acad. Nat. Sci. Phil. 



(1901), p. 112, pi. I, figs. 1-7. 

 1905. Callianassa mortoni Johns, Proc. Acad. Nat. Sci. Phil. 



(1905), p. 28. 



Description. — "Propodite rhombic, its breadth about two- 

 thirds the length, the outer face very convex, the greatest convex- 

 ity posterior and nearer the upper side. Surface nearly smooth, 

 usually showing a series of four distinct punctures extending 

 backward from the root of the fixed finger, and two on the other 

 or more convex side; the posterior margin abrupfly falling near 

 the joint, a prominence bearing a group of small tubercles at the 

 summit before the deflection. Inner surface of palm much less 

 convex, becoming concave near the lateral margins, nearly 

 smooth, the anterior margin slightly excavated between the root 

 of the fixed finger and the dactylopodite, and bordered there with 

 a short row of small tubercles. On the median portion of the palm 

 there are two- punctures, marking it off into thirds longitudinally. 

 Lateral margins of the propodite acute, closely, finely and regu- 

 larly crenulate; the lower margin straight, with a row of punc- 

 tures along the inner side but extremely near the edge, and an- 

 other close to the edge outwardly ; upper margin deeply curved 

 down posteriorly, produced into^ a deflexed lobe and similarly 

 margined with spaced punctures. Fixed finger about one-third 

 the total length o-f the whole propodite, curved at the tip, finely 

 crenate along the grasping margin when unworn, and with a 

 blunt median tooth. Dactylopodite with two contiguous crenulate 

 carinas along its outer edge. Carpopodite somewhat shorter than 

 the palmer surface of the propodite, equally convex inside and 

 out, turgid anteriorly, its outer face with an oblique groove bor- 

 dered with small tubercles near the distal lower angle. Posterior 

 54 PAi, 



