12 PROCEEDINGS OF THE NATIONAL MUSEUM vol. 124 



The models also show an "incenter" of the above species approximately 

 midway between P. xantusii xantusii and P. acuminatus ©. 



Relationships of the remaining American species of Portunus 

 to the western group of nine. — These comprise species @-(H> and 

 also © of table 2. 



Tabular data: Mean values of eastern species to both P. xantusii 

 xantusii and P. xantusii affinis ® were computed and are as follows : 



P. anceps @, NFD 20, TD 4.5; P. bahamensis ©, NFD 16, 

 TD 4.1; P. depressions @, NFD 16, TD 3.7; P.floridanus <g), NFD 

 17, TD 4.2; P. gibbesii ©, NFD 10, TD 3.0; P. ordwayi ©, NFD 7, 

 TD 2.8; P. rufiremus <g>, NFD 17, TD 4.0; P. sayi <§), NFD 24, TD 

 4.8; P. sebae <§>, NFD 9, TD 3.0; P. spinicarpus @, NFD 10, TD 3.2; 

 P. spinimanus @, NFD 6, TD 2.6; and P. ventralis <§), NFD 10, TD 

 3.0. 



If NFD values of 10 or less or, alternatively, TD values of 3.3 

 or less are taken as an arbitrary limit of "close relationship," then the 

 following six species are part of the western American group "centered" 

 near P. xantusii: P. gibbesii ©, P. ordwayi ©, P. sebae ©, P. spini- 

 carpus @), P. spinimanus ®, and P. ventralis (fg). Mean values mutually 

 between species of this now enlarged group of 15 species are NFD 9.6, 

 TD 3.0. These relatively low values indicate a reasonably homogeneous 

 group. 



The remaining American species comprise five species distantly 

 related to the 15-species P. xantusii group: (1) P. bahamensis © and 

 P. depressijrons @, which form a related pair (NFD 7) and are closer 

 to the P. xantusii group than to the remainder. (2) P. anceps ® and 

 P.floridanus @ are a more distantly related pair (NFD 12), also more 

 distant from the P. xantusii group; they are moderately close to the 

 P. bahamensis @/P. depressijrons @ pair (mean NFD 16.3, mean TD 

 4.0). (3) P. rufiremus @ is in an isolated position, being distant from 

 the other four species above; it is closest to P. acuminatus ® (NFD 

 13). (4) The western American P. tuberculatus (fij) is related to the 

 Indo-West Pacific species in the P. longispinosus group (see Garth 

 and Stephenson, 1966; Stephenson and Rees, 1967); because of synon- 

 ymy problems within this group, P. tuberculatus @ was compared with 

 the only "fixed point" available, the holotype of P. macrophthalmus 

 (f|); it is closer to this species (NFD 11) than to the nearest member of 

 of the 15-species group (NFD 13 to P. x. xantusii ®); it is probably 

 closer to other species in the P. longispinosus group, and shows a 

 distant relationship to P. vocans @ (see following). (5) The eastern 

 P. vocans @ is so similar to P. nipponensis (Sakai) 1938 from Japan 

 that numerical techniques are unnecessary; it probably is related 

 distantly to P. tuberculatus (jo), P. macrophthalmus (23), and other 

 members of the P. longispinosus group, but since only a female was 



