NO. 3 COPEPODA FROM PANAMA MARSH IO, 



South America and from Haiti, and it is suggested that this may have 

 been C. tenuis. In that case we should consider C. tenuis as a South 

 American form with a northern limit of southern Arizona. 



Cyclops dentatimanus and C. panamensis are South American in 

 their general relationships. 



Cyclops cequoreus is distributed widely, but has never before been 

 reported from the west coast of America. It seems rather strange 

 that it did not appear in the collections from the east coast, but those 

 collections were few in number, and it is probable that further work 

 will show that it is found there also. 



The genus Pseudodiaptomus has been found in Europe, Asia, 

 Africa, and North and South America. Both the species from .the 

 Pacific coast and that from the Atlantic coast are closely related to 

 South American forms, that from the Atlantic coast being very close 

 to one found in the mouth of the Amazon. 



The three species of Diaptomus, too, find their nearest relatives in 

 South America. 



It is evident then, that the general character of the copepod fauna 

 of the Canal Zone is much more closely related to the South American 

 fauna than to that of North America. When we compare the north 

 and south sides of the isthmus we find common to the .two slopes 

 Cyclops leuckarti, C. tenuis, and C. serrulatus. C. cequoreus we 

 know is not peculiar to the Pacific slope. C. albidus, C. prasinus, C. 

 varicans, C. quinquepartitus, Diaptomus marshi, D. leoninicollinus, 

 D. gatunensis, and Pseudodiaptomus cristobalensis are found on the 

 Atlantic side but not on the Pacific. 



Peculiar to the Pacific slope are Cyclops dentatimanus, C. panainen- 

 sis, and Pseudodiaptomus culebrensis. It will be noted that no 

 species of Diaptomus are recorded from the Pacific slope. It does 

 not follow, however, that none are present. Some immature speci- 

 mens and one mature female were found, but no males, so that no 

 diagnosis of species could be made. We certainly cannot consider 

 Cyclops varicans as peculiar to the Atlantic side, for it is a South 

 American species. In fact there is a reasonable doubt whether any 

 of the species of Cyclops found on the northern slope are peculiar 

 to that locality. Probably the three species of Diaptomus found on 

 the northern side may be considered characteristic of that slope. So, 

 probably the two new species of Cyclops found on the south side, 

 C. dentatimanus and C. panamensis are peculiar to that slope. The 

 species of the brackish water genus Pseudodiaptomus, too, are 

 peculiar, that on the south shore differing from that on the north 

 shore, but both are closely related to South American species. 



