192 CRUSTACEANS. 



There is extraordinary development and action of the pcdipnlpi ; 

 two projecting organs near the mouth, usually very small in other 

 species, from which a distinctive and most appropriate name may be de- 

 rived, as the Fanning or Ventilating Crab, — which will never be thought 

 of, however, by those studying only the form of dried specimens. 



The pedipalpi, as I conclude them, prolonged in six articulations, 

 orio^inate nearly in a horizontal line with the claws, and they extend 

 considerably beyond the margin of the shell. A fringe clothes the inner 

 edge of the four upper articulations with long hairs, though not very 

 profusely ; these organs reciprocally curve towards each other with an 

 alternate see-saw action, as if occupied in ventilation, which is particu- 

 larly evident in the afternoon. 



The animals are externally plain or variegated, much diversity of 

 colour being prevalent among them. The body is uniformly brown, 

 lio-ht, or mottled, the limbs often resembling tortoise-shell. 



Such creatures are very tranquil, concealing themselves wherever 

 they have an opportunity. 



They rarely feed, but sometimes consume mussel. 

 The breeding season is in May and September, spawn then elevating 

 the apron of the female. 



This apron is very large, and of remarkable formation ; the last or 

 internal segment resembhng a quincunx compounded of several pieces. 



Early spa\vn is very compact. It afterwards relaxes in clusters. 

 Many of the detached capsules seemed to me larger than those of other 

 species. Specimens die suddenly. During my inspection of one in ap- 

 parent health, it fell back, and never moved again. 



These animals are recovered in great numbers from deep water. I 

 have not observed that any were taken near the shore. Certainly they 

 were found in greater profusion formerly than of late. 



Plate XLV. 



Fig. 1. Cancer {porcellana) longicornis, male; back. 



2. Female, breast. 



3. Another specimen. 



4. Apron, enlarged. 



5. One of the pedipalpi, or ventilators, enlarged. 



