RELATIONSHIP OF THE FAUNA. 91 



number of species indeed, nearly all of them are, as would 

 be naturally expected, forms which belong to tropical or sub- 

 tropical America (Florida, West Indies, Brazil). None of the 

 species, as far as they have been determined the Isopoda and 

 Amphipoda still await examination are peculiar to the Ber- 

 mudas, excepting possibly Scyllarus scvlptus. The specimen 

 figured by Lamarck in the Encyclopedic, and subsequently de- 

 scribed by Milne-Edwards, seems to have been "without a 

 home," nor have I been able to trace the species from the writ- 

 ings of later authors. I am, therefore, not in a position to say 

 whether the species is strictly Bermudian or not. 



The remarkable fact connected with the Bermudian Crus- 

 tacea is the appearance of three species of Macrurans which 

 had hitherto been recorded only from the Pacific. These are 

 Palsemondla tenuipes, described by Dana from the Sooloo Sea. 

 Pal demon affinis, and Penseus velutinus, the last a species also 

 first described by Dana. It is remarkable that the only 

 species of Palaemonella other than P. tenuipes is likewise an 

 inhabitant of the Sooloo Sea. I am wholly at a loss how to 

 account for the occurrence of these Pacific types at the Ber- 

 mudas; they may yet be discovered in some intermediate 

 region, and thereby lessen the difficulty in the problem, but 

 for the time being their presence must be considered a zoogeo- 

 graphical knot to be cut. The absence of the common Paldemon 

 vulgaris, as well as of the principal crustaceans of the Eastern 

 United States, excepting the more southerly forms, is strik- 

 ingly noticeable. Alpheus avarus is a Eurafrican form ; 

 Pachygrapxus transversus has been noted also from Australia. 



The insect fauna (including here also the spiders) of the Ber- 

 mudas is distinguished more by negative features than by 

 positive ones; it is eminently deficient. It is not yet known 

 in its full details, but sufficiently so to show that it is mainly a 

 combination of Neotropical (West Indian and South Ameri- 

 can) and Holarctic (North American) elements. And here we 

 are presented with the significant fact that the insects proper 



