THE CANCROID CRABS OF AMERICA 



349 



surface than in herbstii, and one misses the scattered round dots 



characteristic of the latter species. 



Varia'Aon. — There is considerable variation even in the same lot of 



specimens. The carapace may be almost smooth and shining or 

 have some slight, granulate, transverse lines. The 

 second tooth of the lateral margin may be small, 

 subacute, similar to the first tooth instead of 

 broadly rounded and larger than the first one. 

 The sides of the sixth abdominal segment in the 

 fema'e may be parallel or nearly so instead of 

 converging slightly toward proximal end. In a 

 lot of six from Brazil (Ilha Governador) the cara- 

 paces are rather more convex and more oval than 

 usual and two large males of subequal size differ 

 remarkably from each other in their antero- 

 lateral margins; in one all the sinuses are deep 

 and all the teeth subtriangular; in the other the 

 sinuses are shallow, the outer margins of the sjc- 



ond, third, and fourth teeth are long and arcuate. Certain assemblages 



of specimens differ in several respects from the typical form and yet 



are not so homogeneous as to warrant a specific designation. They 



may be known as & forma 



FORMA SERRATA Saussure 



Plate 161, Figures 1 and 3 



Differs from true occidentalis in the carapace more rugose, the third, 

 fourth and fifth teeth widely separated and more outstanding, the 

 second tooth usually narrow and subtriangular. Carpus of cheliped 

 rugose. Within the form, the abdomen varies in the amount of con- 

 striction and the carapace varies in shape, leaning either toward the 

 hexagonal or to the oval. 



Measurements. — A smaller species than P. herbstii. 



Figure 55.— Panopeus oc- 

 cidentalis, MALE ABDO- 

 MEN, ENLARGED. After 

 Benedict and Rathbun 



Forma 



typica _ 

 serrata. 



Front 

 width 



Range. — From South Carolina, by way of the Gulf of Mexico, to 

 State of Santa Catharina, Brazil. Bermuda. 



Material examined. — Unless otherwise indicated, the form of the 

 specimens listed below is typical or near typical. 



SOUTH CAROLINA.— Calibogue Sound; Fish Hawk: Off south 

 end of May River; 10 fathoms; hrd.; temperature 51° F.; January 

 16, 1891; station 1651, 1 young female (59491) typical; 6 males, 

 8 females, 8 young (15713), forma serrata. Between stations 1646 

 and 1651; 1 young female (15737), forma serrata. 



