] INTRODUCTION. 
The genera of the sub-family Lystanassina appear to 
be very generally diffused over the entire globe, increasing 
in dimensions in those species that approach nearer to the 
Arctic and Antarctic latitudes, in some instances reaching 
to the largest known of the order, equalling three inches 
in length, as may be seen in Lystanassa Magellanica, from 
the Straits of Magellan, and L. gryllus, from Spitzbergen. 
These two so closely resemble one another, that they can- 
not be characteristically distinguished. 
The genus Ampelisca, and its near ally Haploops, we 
only know as belonging to the Northern Hemisphere, but 
in that region extending from Japan to Europe, from 
Greenland to North Carolina on the coast of America, 
and in Europe to the Mediterranean Sea. 
In the sub-family Puoxina all the genera but one are 
only known in the north temperate region, but with a 
widely diffused area, extending from Japan to Europe. 
One species of the genus Cidiceros has been taken in New 
Zealand, and one of Iphimedia in Terra del Fuego. Of 
the former we have our doubts in its relation to the 
genus; the latter has a very near resemblance to J. Hdlane 
of Europe. Most of the genera of this sub-family are 
burrowers in mud or sand. Jsea dwells, without being 
parasitic, on the back of hairy crabs, and the only 
specimens of Darwinia, that have been taken alive, were 
found adhering to the throat of a cod-fish. The genus 
Sulcator lives on sandy shores, making tracts along the 
margin of the sea, somewhat similar to those found in 
older slate and sandy rocks; and it may be interesting 
to remember that we have attributed to this sub-family 
the only Amphipod that has been hitherto discovered as 
fossil, the Prosoponiscus problematicus of the magnesian 
limestone of Durham, and Zechstein-dolomite of Glicks- 
brun. 
