FROM THE EDDYSTONE GEOUNDS TO START POINT. 493 



Habits. The habit of Corystcs cassivdavnus of burrowing in fine 

 sand was recorded by several of the older naturalists {Couch, Gosse, 

 Robertson), and recently Garstang has made a special study of the 

 species in relation to this matter. He found that the crabs burrowed at 

 once in fine sand, but would not burrow in gravel. They came out of 

 the sand and became active at night. 



DiSTUiBUTiON. Geographical. Mediterranean, Bay of Biscay, English Channel, Irish 

 Sea, West Ireland, southern part of North Sea only (not north of Scarborough) (Marion 

 and Gourret, Pruvot, Bonnier, "Walker, Mctzger). 



Depth. Between tide-marks (Walker) to 30 fatlioms (E. J. A.). 



Bottom-deposit. Corystes cassivelaunus is recorded by Marion and Gourret (Mediter- 

 ranean, Nos. 74 and 31) on mud, rare ; by Pruvot (No. 98), on mud and on sand ; by 

 Metzger (North Sea, No. 78), on sandy mud and on fine sand ; by Holt (West Ireland, 

 No. 48), on sand and on soft mud ; by Walker (Irish Sea, Nos. Ill and 112), on sand. 



Corystes cassivelaunus is a good example of a burrowing species whose distribution is 

 directly controlled by the texture of the bottom-deposit. 



Atelecyclus heterodon (Chart XIII.) was abundant on two grounds, on 

 Ground XIII,, one mile east of the Eddystone, where the bottom-deposit 

 is medium gravel mixed with a considerable amount of mud (see Table 

 II., Sample 103), and on Ground IX., three miles west of the Eddystone, 

 where the deposit is coarse gravel mixed with fine sand (see Table II., 

 Sample 94). On the muddy gravel the specimens were both large and 

 numerous, on the sandy gravel they were numerous, though compara- 

 tively small. On the other grounds in the neighbourhood of the 

 Eddystone occasional specimens only were taken, generally in not more 

 than one haul, as follows : (Cf. Chart XIIL), Ground XI. (one in 47, 

 one small one in 84), Ground X. (haul 42, small in 95), Ground VII. 

 (hauls 38 and 100), Ground XV. (one in haul 97), and Ground IV. (in 

 34 only). One specimen was also taken on the fine sand of the inner 

 trawling ground (I.) in haul 82. On the Bolt Head Ground (XVII.) 

 the species was taken only in hauls 27 and 28, which are the two hauls 

 on this ground furthest from the shore, and differ in other respects 

 from the remaining hauls. One or two specimens only were taken in 

 these hauls, and the bottom is described from observation of the 

 contents of the dredge as shells, broken shell, gravel, and sand. (At the 

 time the hauls were made the taking of proper samples of the deposit 

 with the canvas bag dredge had not been commenced.) On the Prawle 

 Stony Ground (XA'III.) Ateleci/cliis was taken in haul 45 only on a 

 bottom described as gravel, stones, and shells. (No sample taken.) 



Habits. A burrowing species (Garstang, No. 29). 



Distribution. Geofjraphical. Mediterranean, Portugal, Bay of Biscay, Brittany, 

 English Channel, South-West and West Ireland, Ii'ish Sea, Shetlands (common), North Sea 

 (northern portion), Norway to Arctic circle (Marion and (iounet, Pruvot, lioiinier, Bell, 

 Holt, Walker, Nonuan (No. 93), -Metzger). It does not appear to have lieen recorded from 

 the s<nitlierii part of tlie North Sea, nor from tlie ivattegat. 



NEW SEKIES. — VOL. V. NO. 4. ^ ^^ 



