87 



Family PORCELLANIDAE. 



Genus Porcellana, Lamarck. 



Chelipeds bear a dense fringe of long setae 

 on their outer edge ; carpus has a denticulated 

 lobe at its inner lower angle ; hands very 

 large, . . . . . . . . . . P. platycheles. 



Chelipeds devoid of setae ; no denticulated 

 lobe on carpus ; hands narrow, . . P. longicornis, 



Porcellana platycheles. Pennant. 



Porcellana platycheles, Bell, 1853. 

 Porcellana platycheles, Heller, 1863. 



The chief specific characters are the following : dense fringes 

 of long setae on the propodite of the chelipeds ; denticulated 

 process near proximal end of carpus ; carapace slightly longer 

 than broad ; its margins setiferous ; front of carapace divided 

 into three lobes, the central one having a slight median groove, 

 but not divided as in P. longicornis ; chelipeds, very massive, 

 and practically equal ; edges of abdominal segments heavily 

 fringed with setae, especially in the female ; walking-legs also 

 setiferous. 



Size. — Large specimens measure about 14-16 mm., from front 

 to back of carapace. 



General Distribution. — ^This species has a more limited distri- 

 bution than P. longicornis. It occurs on all the British coasts, 

 even as far north as the Orkneys and Shetlands (Bell). It is 

 also found plentifully on the French side of the Channel, and 

 in the Bay of Biscay (Milne-Edwards), o:ff the Spanish and 

 Portuguese coasts, and at the Canaries (Heller). It is very 

 common throughout the shores of the Mediterranean and 

 Adriatic (Heller). 



Irish Distribution. — Found abundantly all round the coast. 

 It is not apparently quite so common on the east as on the 

 west coast, but the larger amount of shore-collecting done 

 on the latter may explain the comparative paucity of records 

 from the east. 



Vertical Distribution. — Very common between tide-marks, 

 and extending only a short distance beyond the low -water 

 line. 



PorceUana longicornis, Linn. 



Porcellana longicornis, Bell, 1853. 

 Porcellana longicornis, Heller, 1863. 

 Porcellana longicornis, Meinert, 1877. 



Carapace almost circular ; the frontal margin divided into 

 three lobes, the central one divided by a deep groove ; the 

 margin of the central lobe is denticulate. Antennules reach 

 beyond the merus of the chelipeds. Antennae, long and very 



