ANCEUS HALIDATI. 207 
strongly defined coloration which his figures represent, 
but the outer pair of foot-jaws in the male of that 
species are formed of a large lunate exarticulate mass. 
The only other species, A. brivatensis, which M. Hesse 
describes as belonging to his first section (to which our 
Irish species seems to be referable), differs in the much 
broader head and in the strongly angulated sides of the 
two anterior segments of the body. Moreover, his 
figure of the underside of the male of A. brivatensis 
shows the outer foot-jaws as of so small a size as not 
closing the mouth, and “ formée d’une lame large ter- 
minée & son extrémité par un petit appendice ovale 
et cilié.” 
In this indecision we have thought it more advisable 
to propose for this Irish species the name of the gen- 
tleman by whom it was discovered, and by whom so 
many interesting additions, in different tribes of annulose 
animals, have been discovered and most satisfactorily 
investigated. 
