PORCELLANOPAGURUS— BORRADAILE. 



113 



Fig. 2. — Porcellanopagurus : side view 

 of the specimen shown in Fig. 1, 

 X 3. Ab, Abdomen ; c, base of 

 cheliped ; s, sixth abdominal 

 tergum ; t, telson ; lo, waist. 



and length, is represented in Porcellanopagurus by a short, deep, forward branch from 

 the cervical groove above the third lobe of each side, and perhaps by a faint forward 

 continuation. 



The substance of the dorsal plate, and of the armour of the first three pairs of legs, 

 is very hard, porcellanous, and a little translucent, not at all like that of most hermit- 

 crabs, but its surface is roughened by many short, 

 transverse ridges, and somewhat sparsely covered 

 with hairs, placed in little rows, each in front of one 

 of the ridges, an arrangement which, developed in « 

 various degrees, is not uncommon in Eupagurinae. 

 Below the projecting lobes of the back-plate, the sides 

 of the cephalothorax (Fig. 2) are almost vertical, 

 though rather low, and they and the hinder part of 

 the thorax are soft, as in an ordinary hermit-crab. 

 The post-cervical region is shorter and wider than in 

 other Paguridae, and the concavity of its hinder 

 edge is semicircular, not deep and narrow, as is usual in the family. In correspondence 

 with this shortening of the region behind and above it, the hinder part of the linea 

 anomurica is directed more downwards than usual. The " line la " of Boas branches 

 as a Y at its upper end, the forward branch joining the linea anomurica opposite the 

 cervical groove, the hinder branch behind the last side lobe. 



On the underside of the thorax (Fig. 3) the legs are set wider apart than in an 

 ordinary hermit-crab, and the sternal series of plates is better developed, though in 

 number and position its pieces faithfully resemble those of Eupagurus. The widely 



separated bases of the third maxillipeds are connected by a 

 slender sternum, rather wider in the middle than at its ends. 

 The two small sternal pieces on the segment of the chelipeds 

 are fused, though their limits are still visible. They are not 

 cjuite symmetrical, the left being rather more prominent than 

 the right; The second pair of legs has a pair of large sternal 

 plates. Behind them stands a transverse piece of good size, 

 which appears to belong to the same segment as the two rather 

 small ossicles at the bases of the third pair of legs. The sternum 

 of the fourth pair of legs is a very narrow bar, placed more 

 cTi, CheHped ; I 3, third clorsally than that of Eupagurus, on the anterior wall of a deep 

 ®^ ' ■\y''^'a ^^^ ° ""^ furrow which separates from the cephalothorax a region con- 

 sisting of the last thoracic segment together with the abdomen. 

 On the hinder side of this furrow, thus seeming to belong to the abdomen, stands the 

 sternum of the fifth pair of legs, which is also a very narrow bar. The oviducal opening 

 is placed, not, as usual, on the ventral side of the coxopodite of the third leg, but on 

 the hinder face of the joint, which is directed towards the furrow between the last 



R 2 



mxp 



Fig. 3. — Porcellanopagurus: 

 third to sixth thoracic 

 sterna of the specimen 

 shown in Fig. 1, X 3. 



