FROM THE EDDYSTONE GROUNDS TO START POINT. 475 



Distribution. Geographical. Both sides of North Atlantic, Norway, Iceland, Medi- 

 terranean, Azores, Florida, Caribbean Islands, North Brazil (A. Agassiz, No. 1). 



Depth. Between tide-marks (Forbes, No. 22) to SOo fathoms (A. Agassiz, No. 1). 



Bottom-deposit. Mobius and Biitschli (No. 88) record Echinocyamus pusillus from stony 

 ground, from shell and sand, and from sand and mud. Meissner and Collin (No. 76) found 

 it at a great number of stations, and apparently upon all kinds of bottom from rough 

 ground to nuid. Petersen (No. 95) in the Kattegat took it generally on sand, occasionally 

 on the mixed ground (sand and mud). He found plant remains, diatoms, and foraminifcra 

 in the stomach. Hcrdman (No. 40) records it from nullipore bottom and from shell sand. 

 It thus apjiears that the species can live under a great variety of conditions as regards the 

 nature of the Iiottom-dcposit. 



Spatangus purpureus. Chart V. This, being a burrowing species, is 

 much more restricted in its distribution by the texture of the bottom- 

 deposit than those urchins, such as Echinus esculent us, which have a 

 wandering habit. On the grounds examined during the present investi- 

 gation it is almost entirely confined to clean shell gravel and fine clean^ 

 gravel. It was most abundant and the specimens were largest on the 

 shell gravel ground south of Bolt Head (Ground XVII.). Next to this 

 ground it was most numerous on the clean shell gravel west of the 

 Eddystone (Ground XVI.) and on the fine gravel just outside this 

 (Ground XIV.), on both of which grounds it was frequently taken. 

 Occasional specimens were found on Grounds VII., VIII., and X., the 

 grounds immediately adjoining the two last-mentioned, and also on the 

 Prawle Stony Ground (XVIII., hauls 45, 63, and 29). The species was 

 never taken on the fine sand nor on the coarse gravel. The bivalve 

 mollusc, Montacuta subsiriata, was generally found attached to the spines 

 of Spatangus. 



Habits. The way in which Spatangus burrows by means of its short, flat bristles was 

 described by Osier in 1826 [Phil. Trans. Roy. Soc, 1826, p. 347). The animal is able to 

 sink almost vertically in the gravel in which it lives, and when lialf buried, at any rate, can 

 progress forwards through the gravel, leaving a deep furrow behind it. The intestine is 

 generally found to be fdled with fine sand and silt (c/. Mobius and Biitschli, Petersen). 



Di.STRiBUTioN. Geographical. East side of the Atlantic from the Azores to Iceland, 

 North Sea, Mediterranean, Bermuda {fide Bell, No. 7). 



Depth. 5-530 fathoms (Jide Bell). 



Bottom-deposit. Forbes (No. 22) found S. purpureus abundant on scallop-banks off the 

 Isle of Man, generally on the cleanest part of the bank amongst tlie scallops. Mobius and 

 Biitschli (No. 88) record it on fine sand, on shell and small stones, on coarse gravel, and on 

 sand ; frequent only on the fine sand. Meissner and Collin (No. 76) give seven records, 

 all from coarse ground, viz., on coarse sand and gravel, on shell and small stones, on shell, 

 on stones and coarse sand, on shell and stones, and on coarse sand and stones. Petersen 

 (No. 95) found it in the Kattegat at eight stations, at six of which the bottom-deposit was 

 coarse sand or gravel. Once he records it from 15^ fiithoms on sand with a little mud (sta. 

 437), and once from 70 fathoms on mud and line sand (sta. 58). Iladdon (No. 34) found 

 it on coarse sand at the mouth of Bautry Bay. Bourne (No. 11) on fine sand in 200 

 fathoms. From the Liverpool district (No. 41, p. 137 ; No. 40, Vol. VIII., p. 20 ; Vol. 

 IX., pp. 34 and 37) it is noted on muddy gravel near Beaumaris, on .shells, stones, 

 and echinoderm spines, on dead shells, shell sand, and ecliinodcrm spines, and on " reaniy " 

 bottom. 



