NO. 3570 PANDARIDAE — CRESSET 19 



with outer edge of exopod first segment with long hairs and short 

 spinules. Leg 3 (fig. 93) with outer edge of exopod first segment 

 bilobed. Leg 4 (fig. 94) with outer edge of exopod first segment 

 similar to that of leg 3. Leg 5 (fig. 95) situated on midlateral margin 

 of genital segment and consisting of a lobe bearing 4 spines, 1 naked 

 and 3 smaller and plumose. Leg 6 (fig. 96) situated at point of 

 attachment of abdomen to genital segment and consisting of lobe 

 bearing 3 spines (1 plumose and 2 naked). Color in life cream, 

 generally devoid of pigment. 



Discussion. — This species thus far has been collected only from 

 carcharinid sharks of the western central Pacific Ocean. It is closely 

 related to P. zygaenae but can be separated from this species by the 

 nature of the dorsal thoracic plates. The plates of the second thoracic 

 segment of P. katoi extend only to about the middle of the plate of 

 the fourth segment, whereas in P. zygaenae these plates extend to the 

 distal end of the plate of segment 4, Since the appendages of these 

 2 species are identical, it seems probable that they have evolved 

 from a common ancestor and thus are very closely related. Because 

 I was able to examine several collections of each species (10 collections 

 of P. katoi, 4 collections of P. zygaenae) , a good sample for comparison 

 was available. In each case the copepods are separated easily on the 

 aforementioned characters, 



I have named this species for Mr. Susumu Kato, who originally 

 collected the type material and who has generously collected in the 

 Pacific area for me. 



Pandarus zygaenae Brady, 1883 



Figures 97-99 



Pandarus zygaenae Brady, 1883, p. 134. — Bassett-Smith, 1899, p. 467. — Wilson, 

 1907, p. 416. 



Specimens studied. — Collections from the following areas: Off Sao 

 Paulo, Brazil, from Sphyrna zygaena (Linnaeus); Pacific (9°47' N, 

 85°48' W) from Sphyrna species; Pacific (18°31' N, 109°34' W) from 

 Sphyrna zygaena. 



Female. — Body form as in figure 97. Total length (based on an 

 average of 2 specimens) 7.6 mm. Greatest width (measured at the 

 widest part of the cephalon) 3.9 mm. Cephalon somewhat truncated 

 and measming 3.7 by 3.9 mm, somewhat wider than long. Thoracic 

 plates present on segments 2-4. Plates of segment 2 extending 

 beyond those of segment 3 and to distal border of plate of segment 

 4. Genital segment somewhat longer than wide (2.7 by 2.3 mm). 

 Abdomen 1 -segmented and with dorsal plate. Caudal rami as in 

 P. katoi except that they are generally held parallel to each other. 



Oral area and aU appendages like those of P. katoi with the follow- 



