Host and Habitat Relationships 615 



the classes Chondrichthys and Osteichthyes and 14 species of in- 

 vertebrates, representing five phyla. 



RESULTS AND DISCUSSION 



The generic distribution of bacteria in the commensal floras 

 of vertebrates and invertebrates from the Pacific Ocean are 

 shown in Figure 1. Gram-negative organisms of the Pseudomon- 

 as/Achromobacter/Flavobacterium group were preponderant on 

 both groups of animals. In both cases, representation of Gram- 

 positive groups was very low. Generally, the populations of bac- 

 teria harbored by marine vertebrates and invertebrate animals 

 are similar. However, there are detectable differences in the re- 

 presentation of the Pseudomonas/Achromobacter and the Flavo- 

 bacterium groups. Vertebrate animals apparently carry greater 

 numbers of Fseudomonas sp. and Achromohacter sp. and inverte- 

 brates greater numbers of Flavobactenum spp. Also, Micrococcus 

 sp. are generally found in greater numbers on invertebrate ani- 

 mals. 



In Figure 2, the results obtained from comparisons of the 

 bacterial flora of vertebrate animals caught in Puget Sound and 

 near Eniwetok Atoll are given, representing the possible effects 

 of habitat between a cold water and a warm water environment. 

 However, apparent differences, though detectable, were small. 

 Gram-negative organisms of the general Pseudomonas/Achromo- 

 bacter/Flavobacterium grouping dominated both floras. Ach- 

 romobacter sp. were somewhat more plentiful in the Puget 

 Sound samples, and so were Flavohacterium sp. On the other 

 hand, enterobacterial types (non-fecal) were present in notably 

 higher numbers in Eniwetok Atoll samples. 



A similar comparison of the bacterial flora of invertebrate 

 animals caught in Puget Sound and Eniwetok Atoll is shown in 

 Figure 3. Gramnegative organisms again predominated, but 

 greater differences in the balance of the populations were noted. 

 Achromohacter sp. were much more abundant in the warni water 

 samples and Flavohacterium sp. were completely absent. Sur- 

 prisingly, perhaps, there was little difference in the numbers of 

 enterobacterial types. 



The overwhelming importance of Pseudomonas and Achro- 



