ARCTURUS. 363 
Milne Edwards): 1. Arcturus Proper, containing Idotea 
Baffmi, and 2, Leacia, Johnston, containing Oniscus 
longicornis, Sowerby (to which Dr. Johnston, regarding 
it as undescribed both generically and specifically, had 
given the name of Leacia lacertosa). Mr. H. Goodsir, 
however, considered the two sections as of generic rank, 
and accordingly retained the name Leachia for the 
British species. Until recently, a single British species 
has only been recognized. The late lamented Harry 
D. S. Goodsir, Surg., R.N., however, detected two 
other species, of which he published descriptions and 
figures in the 3lst volume of the “ Edinburgh New 
Philosophical Journal.” Living specimens of all these 
three species were captured by Mr. Goodsir with the 
dredge in deep water in the Frith of Forth, and in the 
German Ocean, but all these were found to be rare in 
consequence of their pelagic habitat. Having kept these 
animals in glass jars of sea-water, with sand and coral- 
lines, Mr. Goodsir was enabled to watch their habits 
closely. Under these circumstances each individual will 
select a branch of coralline, keeping that branch ex- 
clusively to itself, and defending it with the greatest 
vigour against all intruders. It fixes itself to its resting- 
place by means of its true feet, which it seldom uses for 
progression, When it falls to the bottom of the vessel, 
it fixes its long-pointed antenne into the sand, and with 
the assistance of the true feet drags and pushes itself 
forward. This, however, may not be a natural mode of 
progression, but may be adopted in consequence of the 
artificial circumstances in which the animal is placed. 
The ordinary and natural mode of progression of these 
animals is swimming. It is amusing to see one of these 
animals resting in an erect posture, on a branch of coral- 
line, by means of its true feet, waving its body back- 
