NO. 2343. NEW TERTIARY DECAPOD CRUSTACEANS— RATH BUN. 383 



Relationship. — I have placed this form in a separate species from 

 the preceding on account of its thin, flattened finger, the propodal 

 finger of maoensis being subcylindrical, or almost circular in cross 

 section. 



PORTUNUS OrJLONGUS, new species. 



Plate 25, figs. 3 and 3a. 



Material. — One carapace of male, with sLernum and abdomen, 

 and bases of maxilliped, of chelipeds and of first two ambulatory 

 legs; from blufl^ on right bank of Rio Mao, about 1|^ to 2 miles above 

 Paso Bajito at Cercado de Mao, Province of Santiago, Dominican 

 Republic; Cercado formation; lower Miocene series; May 4, 1919; T. 

 W. Vaughan and C. W. Cooke, collectors (8522: C-28-19). Fossil 

 from 15 to 30 feet above water. Cat. No. 328229, U.S.N.M. 



Vescrvption. — Anterior part of carapace missing as far back as 

 the line at the anterior base of the fifth lateral tooth. The last four 

 small lateral teeth are more or less completely preserved, the spines 

 at the lateral angles are large, but are broken off near the base. The 

 carapace is very uneven and shows granulations especially on the 

 teeth and on the postlateral margin; it is unusually wide, 104 mm, 

 measured in front of lateral spine, while the distance from the same 

 point to the anterior base of the fifth tooth is only 22.1 mm. The 

 fifth tooth has a convex posterior and a concave anterior margin. 



The ischium of the right maxilliped shows a deep furrow, which 

 is situated near the inner third and does not reach the posterior end. 

 The cross section of the ischium of the cheliped is triangular and 

 indicates a very stout segment. 



The sternum between the chelipeds is extremely wide, giving the 

 whole sternum a more oblong shape than usual ; its margin opposite 

 the anterior base of the cheliped bears a few granules; sternum in 

 front of the articulating condyle of the cheliped depressed, the line 

 between the depression and the elevation behind it being transverse^ 

 not V-shaped. The abdomen, exclusive of the first two segments, is 

 triangular; the length of the coalesced segment (third, fourth, and 

 fifth combined), measured on the median line, from the transverse 

 ridge to the distal end is two-thirds of its distal width; the sixth 

 segment is half as wide on its distal as on its proximal margin, while 

 the length is three-fourths of the proximal width; terminal segment 

 triangular, its width a little greater than its length. 



Relationships. — This specimen compared to the male of P. gahbi,^ 

 has a wider carapace and a different shaped lateral tooth; in galhi 

 the fifth lateral tooth is convex on its posterior margin at the base 

 only, becoming suddenly slender toward the tip; the abdomen of 

 gabhi, so far as it is visible, is wider and more oblong. 



1 Rathbun, I'ubl. No. 291, Carnegie Inst., Washington, 1919, p. 172, pi. 3, figs. 2-7; pi. 6, figs. 1-2. 



