NOTES ON CORNISH CRUSTACEA. 



287 



been overlooked on account of its small size and habits. It has 

 been taken about a mile south of Long Rock, Mount's Bay, in 

 6 fathoms in Pentle Bay, Scilly, and by Vallentin in 10 fathoms 

 in St. Ives Bay. 



The Nipper Crab, Polybius hensloivii, Leach, is either migra- 

 tory or nomadic. Males occur abundantly at times on sheltered 

 stretches of fine sand in shallow water as at Cawsand Bay, 

 Mevagissey, Mount's Bay, St. Ives Bay, and in June, 1906, in 

 Towan Bay, Newquay. It has been several times captured at 

 Looe, and occasionally appears in small numbers at Polperro. 

 In July, 1901, and again in September, 1904, a few were taken 

 in Gerrans Bay. In Falmouth Bay it was found by Cocks only 

 in the stomachs of fishes, and is still one of the rarest of Crabs 

 there, a single specimen taken in June, 1906, being the only 

 record, though in October, 1905, the dredge was suddenly filled 

 with males in 45 fathoms of water about fourteen miles east of 

 Ooverack. This Crab is a powerful swimmer, capable of moving 

 with speed and agility, and pursuing Pilchards and Mackerel in 

 and about the fishermen's nets with singular pertinacity. Large 

 shoals are occasionally met with far out at sea. In April, 1901, 

 several hundred were taken in a Mackerel-net twenty-five miles 

 W.S.W. of the Eddystone, and in June of the same year a 

 Pilchard boat reported them in quantity sixty miles south-west 

 of the Dodman. In May, and again in June, 1903, great 

 numbers were captured in Pilchard-nets some distance west of 

 the Bishop Lighthouse at Scilly. In June, 1904, a very large 

 shoal was recorded by a Mackerel boat from seventy miles 

 N.N.W. of St. Ives ; while in June, 1907, it was abundant five 

 miles south-east of the Wolf. Though the species is so common 

 around the county, the writer has never seen a female captured 

 in Cornish waters. 



Portumnus latipes (Pennant), with body-colour of light purplish 

 yellow, splashed and streaked with pale lilac, is the most beauti- 

 ful of all the Cornish Crabs, but is unfortunately very scarce. 

 As it burrows about spring-tide low-water mark on sandy 

 beaches, it may of course be generally overlooked. In May, 

 1902, several dead but perfectly fresh specimens were picked up 

 at Helford ; in June, 1905, a dead male was found on the beach 

 opposite Godrevy ; and in August, 1907, a living male was 



