112 



TERRA NOVA " EXPEDITION. 



h " of Boas * — and extends backwards a little way beyond the cervical groove. In 

 Porcellanopagurus (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 ridge. The first side-lobe stands at the angle of the 

 carapace, above the antenna. The second has, in P. edicardsi, three cusps, of which 

 the foremost is low and blunt, the middle long and sharp, and the hinder a mere knob. 

 Tlie 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 sanall 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 linea thalassinica 

 — of which a trace exists in other Paguridae, in the form of a groove of varying depth 



* K. Dansk Vidensk. 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. 



