Synopsis of the American Sesarmse. 91 



I/. Margins of meri of ambulatory legs converging 



from the middle towards the carpal joints. 

 M. Front deeply concave ; protogastric lobes 

 strongly projecting. angusta* Smith. 



M'. Front slightly concave ; protogastric lobes 

 slightly projecting. 



angustipes Dana = americana * Saussure. 

 D / . Protogastric or supra-frontal lobes smooth or nearly so. 

 E. Front less than 4 times as wide as high. 



ricordi* Milne Edwards = guerini* Milne Edwards min- 

 iata* Saussure = angustipes Stimpson (in part,* at least) 

 = angustipes Smith* = stimpsonii Miers,* 1881, not 1880, 

 cinerea Heilprin,* 1888, = cinerea Ives,* 1891. 

 E x . Front more than 4 times as wide as high. 



kanseni Rathbun, new species. 



Sesarma (Holometopus) miersii Rathbun, new name. 



Sesarma angustipes? Miers, Proc. Zool. Soc. London, 1881, 70, Rat Island, 



Monte Video. 

 Sesarma stimpsonii Miers, Challenger Rept., Zool., XVII, 270, 1886; not 



8. stimpsonii Miers, 1881. 



Carapace broader than long, of equal width anteriorly and posteriorly, 

 surface more convex than in S. cinerea, regions deeply marked. Carapace, 

 as in 8. roberti, punctate, the pnnctee crowded in places and tending to 

 coalesce ; anterior portion rough with tubercles. Kxcept for its width, the 

 carapace has great resemblance to that of S. roberti. 



Front less than four times as wide as high. Superior lobes less promi 

 nent than in S. roberti. The middle sinus of the lower margin when 

 viewed from above is much shallower and less rounding than in that 

 species. Viewed from in front the lower margin forms an almost un 

 broken convex line. The side margins of the front diverge below as in 

 S. ricordi. 



The lateral margins of the third abdominal segment of the male are 

 arcuate, the abdomen being widest posterior to the distal end of that seg 

 ment. The terminal segment is as wide as it is long. The appendages 

 terminate in an oblique sinuous margin fringed with hair. 



The chelipeds resemble pretty closely thtfse of S. roberti. The meri of 

 the ambulatory legs are shorter than in that species, being less than 2 

 times as long as wide in the first, third, and fourth pairs, and a little more 

 than 2J times the width in the second pair. Propodi of first and second 

 pairs hairy above and below ; those of the third and fourth pairs hairy 

 only on the distal portion. 



Dimensions. tf, Abaco, Bahamas, U. S. Nat. Mus., No. 11372 : Length, 

 19.3 mm.; width, anterior and posterior, 21.1 ; superior frontal width, 11 : 

 inferior, 11.6; depth of front, 3; length of merus of third ambulatory 

 leg, 15.3 ; width of same, 6.3. In some specimens the posterior width is 



*Type examined by the writer. 



