358 L. E. CRAWSHAY. 



CANCKIDAE. 

 Cancer pagurus, Linnaeus. 



One large specimen at Position 25, and two specimens at Position 64. 



Depth, 46-50 fath. 



At the former point the haul was one of eight minutes' duration, 

 made with the triangular dredge, the bottom consisting of shell and 

 gravel mixed with small stones. At the latter point the otter trawl 

 was used for half an hour, and as no stones were touched by this, and 

 few by the dredge haul immediately preceding it, it may be assumed 

 that the ground was soft and comparatively free from them. 



Xantho tuberculatus, Couch. 



At Positions 9 (one ovigerous female), 28 (one ovigerous female), 

 33 (one), 36 (one ovigerous female), 4-4 (one), 58 (one male), 59 

 (two females), 63 (one), \di (one female), 80 (one). 



Depth, 44-50 fath. or over. 



Of the three ovigerous females recorded, two (at Positions 9 and 36) 

 were secluded in empty shells of Buccinum undatum, and the zoaea 

 larvae hatched out off the last one on the following day. 



The species was discovered by E. Q. Couch, who found it repeatedly 

 in the crevices of Lcprcdia foliosa in the deep water in Mount's Bay, 

 Cornwall, but states that it approaches the shore, being found under 

 stones in summer, and breeds in June. Though it has been recorded 

 from Liverpool Bay, and more recently from Cumbrae in Scotland, 

 it is especially characteristic of the extreme south-western British 

 fauna, and even its inclusion among the species of Plymouth Sound, 

 properly speaking, is open to doubt. Garstang (6, p. 339) records 

 its addition to the Plymouth type collection, but with no data as to 

 its locality. An earlier record by Heape (8, p. 170), " Frequent, 

 4-45 fathoms," included in a list compiled by Bate, involves the 

 same question of locality, since the material concerned is only referred 

 to by the last author in his original report (2, p. 276), as collected 

 "mostly between Bigbury Bay towards the east and the Dodman 

 towards the west," and "within a distance of about twenty miles of 

 the shore in water that has not exceeded fifty fathoms in depth," 

 thus defining the area for the whole list recorded. The point is of 

 some importance because Xantlio tuberculatus is one of those species 

 which appear to be rather definitely limited in distribution by certain 

 physical conditions associated with the extreme western area of the 

 Channel, outside the influence of which they exist only in diminish- 

 ing numbers and soon disappear from the fauna. 



