470 ON THE FAUNA AND BOTTOM-DEPOSITS NEAR THE 30-FM. LINE 



Ophiura njinis. One specimen only on the Bolt Head Shell Gravel 

 Ground (XVII., haul 28). 



Habits. With reference to the animals of this species Hodge (No. 47) remarks upon 

 "their excessively lively movements ami the wonderful pliability of the rays." 



DiSTRiBi'TioN. Geographical. East and west coasts of North Atlantic and Mediterranean 

 {vide Lyman, No. 71 ; Hoyle, No. 51 ; and Bell, No 7). 



Depth. 10-192 fathoms (Lyman and Bell), 267 and 294 fathoms (Mobius and Biitschli, 

 No. 88). 



Bottom-deposit. Mbbins and Biitschli {Pommcrania), on mud at 267 and 106 fathoms, 

 on sand, on muddy sand, on sand and shell with small stones. Petersen (No. 95) found 

 it in tlie Kattegat chiefly on sand and on sand and nuul. Meissnor and Collin (No. 76), 

 on sand and mud, on coarse sand and stones, on mud and stones, on sand and shell, on 

 mud, on fine dark sand, etc. It is evident that the species, like 0, ciliaris and 0. albida, 

 lives on a great variety of grounds. 



Ophiadis Balli (Chart IX.). This species is confined to the gravel 



and stony grounds. It is found hidden away in crevices between 



masses of Chaetoptcrus tubes, and in similar places. It is entirely 



absent from the sandy bottoms. 



Habits. I can onl}^ confirm the statement of Norman (quoted by Bell, No. 7), viz., "it 

 lives on liard ground, in deep water, and has a peculiar habit, delighting to nestle in 

 hollows and crevices of stones, squeezing its disk and tAvisting its arms so as to conform to 

 all the irregularities of the surface to which it attaches itself." 



Distribution. Gcograjyhical. Scandinavian and British Coasts (Hoyle, No. 51), Bay 

 of Biscay (Koehler, Nos 60 and 61), 



Depth. The deepest record is 240 fathoms (Hoyle, No. 50). 



Bottom-deposit. Sand and gi-avel (Hoyle, No. 50), hard ground (Norman). Koehler 

 records it from the Monaco dredgings from 50-100 fathoms on coarse ground, and once from 

 the Caudan on coral ( Lophohelia) from 200-270 fathoms. 



Ophiocoma nigra (Chart YIII.). The only ground amongst those 



investigated where 0. nigra is at all common is the Prawle Stony 



Ground (XVIII). On the gravel north-west of the Eddystone a few 



specimens were taken in one haul only (No. 47), on Ground IX. 



Occasional specimens were found on the gravels west of the Eddystone 



(IX., X., XII., XIV., XVI.) and on the Bolt Head Shell Gravel (Ground 



XVII.). The species is entirely absent from the fine sand grounds. 



Habits. Mobius and Biitschli (No. 88, p. 146) state that 0. nigra is fond of climbing up 

 the vertical Avails of a vessel in which it is living, from which they conclude that the species 

 climbs rocks. A similar habit of the s[)ccies has often been noticed in the tanks in the 

 Plymouth Laboratory. The authors mentioned record 0. nigra from live of the stations 

 dredged by the Pommerania, at four of which it was abundant, and the ground is 

 described as stony, at one it was scarce, and the ground was white, granular sand rich 

 in Foraminifera. As will be seen below, it is in such stony places that the si>ecies is 

 generally numerous. It Avould seem, therefore, that its general habit is to climb about 

 amongst stones. Petersen (No. 95, p. 47) states tliat tlie stomachs of his specimens were 

 filled with mud (Bundmateriale), containing vegetable remains. 



Distribution. Geogra^yhical. Ophiocoma nigra is a northern species. It is found on 

 all British Coasts, in Norway, Kattegat (rare, Petersen, No. 95), and Barent's Sea {fide 

 Hoyle, No. 51). I have seen no record of it from more southern waters. 



Depth. The greatest dejjth recorded is 87 fathoms (Hoyle, No. 50, p. 714). 



Bottom-deposit. Mobius and Biitschli record 0. nigra from stony places. Petersen found 

 the species at five stations only in the Kattegat on gravel and stony grounds, stones being 

 recorded from four of the stations. Hoyle's record from 87 fathoms was from a bottom of 



