FllOiM THE EDDYSTONE GROUNDS TO START POINT. 461 



The species is found in abundance, in a very similar situation, by the 

 side of the ledge of rock running westward from the Plymouth 

 Mewstone. Near this ledge the bottom-deposit is clean shell gravel, 

 and //. nigra is generally obtained by working a dredge or trawl over 

 this gravel, keeping parallel to the ledge and close to it. We have 

 found no other locality in the neighbourhood where any but very 

 occasional specimens are taken. 



A possible explanation of these facts is that the animal is really a 

 rock-haunting species, but that owing to the tenacity with which it is 

 able to cling it escapes capture on rocky ground by any of the methods 

 of collecting ordinarily used. If this be the case the specimens taken 

 on the shell gravel, as described above, must be regarded as immigrants 

 from the neighbouring rocks. 



Habits, In confinement Holothuria nigra shows its climbing habit by spending a great 

 deal of its time clinging to the sides of the tank in -which it is placed. 



The nature of its food is indicated by the fact that when captured the intestine is filled 

 with fine sand and silt containing diatoms and organic remains. 



The habit of this species of using the sticky thread secreted by the Cuvierian organs as 

 a means of defence is well known. 



Distribution. Geographical. Norman (No. 92) records the species from Plymouth, 

 South Cornwall, south-west of Ireland, Naples (= H. Poll), Lesina (= 11. catanensis), and 

 IJay of Biscay. Bell (No. 7) records specimens from the west of Ireland, from Cornwall, 

 and from Plymouth. Holt (No. 48, p. 280), Herdman (No. 40, Vol. V., p. 201), and 

 Gamble (No. 26) all took IT. nigra on the west coast of Ireland. 



Depth. Herdman found the species between tide-marks, at Inishbofin, on the coast of 

 Conuemara, and Gamble in a similar situation at Valencia. The greatest recorded dejith 

 for the species is 30 fathoms (Bell, No. 7). In the Plymouth district it is taken in from 

 16 to 30 fathoms. 



Bottom-deposit. Herdman's specimen was taken under a ledge of seaweed-covered 

 rocks on the shore. Holt trawled specimens in 16 to 13 fathoms from a bottom described as 

 sand and rock. 



Astropeden irregvlaris (Chart VIII.). The distribution of this 

 species on the Eddystone to Start Grounds is shown in Chart A^lll. 

 The species in this neighbourhood is a typical representative of a fine 

 sandy bottom. It was found in greatest abundance on the clean sand 

 (Ground III.) 3-4 miles E.N.E. of the Eddystone, where the proportion 

 of silt was small (see Table 11., p. 525). It was also constantly taken, 

 though in somewhat smaller numbers, on the outer and inner trawling 

 grounds (Grounds I. and II.), where the sand is finer and contains a 

 larger percentage of silt (see Table II.). 



But the species is not entirely confined to the fine sand. As will be 

 seen from the chart, it is present, though rare, on the gravel and broken- 

 shell grounds around the Eddystone (IX., XI., XIII., XIV., and XVL), 

 one or two specimens being taken occasionally on each of these 

 grounds, though by no means in every haul. On the sand immediately 

 outside these gravels (IV., VI., and VII.) the species is also rare. 



On the Bolt Shell Gravel (XVII.) and on the Prawle Stony (Jround 

 (XVIII.) Astropeden has never been taken. 



NEW .SKKIES. — VOL. V. NO. 4. 2 U 



