NO. 3645 



PORTUNIDAE — STEPHENSON, WILLIAMS, LANCE 



11 



examples of analogous pairs in other crustacean groups should be 

 re-investigated. 



Relationships among western American groups of Portunus. — 

 These comprise species ©-©, inclusive, of table 2. Consideration of 

 NFD or TD values or inspection of the models shows that P. tuber- 

 culatum © is distant from the remainder, as known already from the 

 classical studies. 



Tabular data: The remaining nine species give mean values (of 

 each species considered in relation to the remainder) as follows: 



P PELAGICUS GROUP 



Figure 4. — Model from NEWGOWER ordination based on an oblique photograph taken 

 from the "southwest" (dotted lines = species groups). 



P. acuminatum ©, NFD 6.3, TD 2.3; P. angustus ©, NFD 

 7.6, TD 2.7; P. asper ®, NFD 6.1, TD 2.4; P. brevimanus ©, NFD 

 11.0, TD 3.3; P. guaymasensis ©, NFD 8.0, TD 2.8; P. iridescens ©, 

 NFD 8.8, TD 2.8; P. stanjordi ©, NFD 7.3, TD 2.7; P. xantusii xantusii 

 ©, NFD 5.4, TD 2.2; and P. xantusii affinis ©, NFD 5.6, TD 2.3. 



These data suggest that P. xantusii with its two subspecies 

 ® and © and also P. acuminatus © are close to the "morphological 

 center" of the western American species of Portunus. 



Inspection of the models: These show that the above nine species 

 are grouped closely with the possible exception of P. brevimanus ©. 



