112 
“ TERRA NOVA ” EXPEDITION. 
/' of Boas —and extends backwards a little way beyond the cervical groove. In 
Porcellanojmgwrus (Fig. 5) its edges have grown out into a series of lobes, by which the 
spread of the back is increased. One of these lobes is a large, triangular rostrum, and 
there are on each side four others, which vary in size and shape according to the species. 
The rostrum bears a low median riclge. The first side-lobe stands at the angle of the 
carapace, above the antenna. The second has, in P. edwardsi, three cusps, of which 
the foremost is low and blunt, the middle long and sharp, and the hinder a mere knob. 
The third and fourth lobes, like the first, are simple. The fourth stands behind the 
Fig. 1.— Porcellanopagurus sp., probably P. edwardsi, taken by the “ Terra Nova” north of 
New Zealand : dorsal view of a berried female, X 3. 
cervical groove on a fairly wide piece of hard cuticle, which in ordinary hermit-crabs 
is represented by a much narrower strip. Besides the ossicles of the fourth pair of 
lobes there is a little post-cervical calcification in the cardiac region. The cervical 
groove which separates this hinder series of small pieces from the main part of the 
back-plate is undoubtedly here, as in other hermit-crabs, the hinder of the two furrows 
to which that name has been applied,f the anterior cervical groove being absent in all 
Paguridea. The horizontal “ line d ” of Boas—the anterior part of the linen thalassinica 
of which a trace exists in other Paguridae, in the form of a groove of varying depth 
K. Dansk Yidensk. Selsk. Skr. (6) I, p. iv. 
f See Gardiner’s “ Fauna of the Maldives,” Art. “On the Classification and Genealogy of the Reptant 
Decapods,” vol. II, p. 690. 
