CRUSTACEA. 



The nearest approach of the Amphipoda to the Isopoda, or rather, 

 to the Anisopoda, takes place in the Caprellidea and the Gammaridea. 



In the Caprellidea the resemblance to Isopods is close in general 

 form ; the broad Cyami have the habit of a Cymothoidan, and the 

 lank Caprella, that of a Tanais or Arcturus. 



The Gammaridea are, in general, widely diverse from the Isopods, 

 through the long inflexed abdomen, which is used in locomotion, often 

 as an organ for leaping, and their thoracic legs, which are unfit for 

 walking or clinging. Yet, there are genera representing the Caprellidea 

 and Anisopoda, which have a gressorial habit. In Goropliium and the 

 related genera the species are simply gressorial; while the genus 

 Dulichia includes slender species that cling by their hind legs, like 

 Caprella and Tanais, and have a similar mode of life. 



The subtribes which have been enumerated, are distinguished as 

 follows : — 



Subtribus I. Caprellidea. — Maxillipedes caputque ac in Gammarideis. 

 Abdomen obsolescens. 



Subtribus II. Gammaridea. — Maxillipedes palpiformes, elongati, 5-6- 

 articulati. Caput oculique mediocres. Appendices abdominales 

 saepius perangustae. 



Subtribus III. Hyperidea. — Maxillipedes operculiformes, breves. 

 Caput grande, oculorum corneis plerumque tectum. Appendices 

 abdominales ssepius latiores. 



Subtribe I. CAPRELLIDEA. 



The Caprellidea pertain to two families, as laid down by different 

 authors : — 



Fam. I. Caprellidjs. — Corpus anguste elongatum, fere filiforme. 

 Antennae 2dae longitudine mediocres. [Species non parasitica^.] 



