184 DEEP-SEA ZOOPHYTES. 



of the Star-fishes j the Sea Cucumbers have an equally 

 singular habit of a similar kind. As their skin is too 

 tough and strong to admit of voluntary dismemberment, 

 they resort to the unique mode of vomiting up their 

 intestines in fact, the whole of their internal organs. 

 Yet it does not appear that life is destroyed by this 

 process. At least, it does not suddenly cease; and, 

 according to the observations of Sir J. G. Dalyell, the 

 lost parts are renewed, after months have elapsed, even 

 in cases where the disembowelling process has been car- 

 ried to an extreme point, leaving " the body an empty 

 sac." Holothurise are often taken with their internal 

 parts more or less deficient, yet apparently existing in 

 health and vigour : in such, probably, the lost parts are 

 in process of restoration. 



Many interesting members of the class of Zoophytes, 

 or compound Polypes, are met with in dredging, a 

 general account of whose classification has been given in 

 a former chapter. For a more specific account of the 

 deep-sea species, I must refer to Dr. Johnston's admira- 

 ble work on the subject, and will here just notice some 

 of the other ASTEROIDA, which I purposely omitted when 

 speaking of the other two orders, HYDROIDA and HE- 

 LIANTHOIDA. This group is distinguished from either of 

 the others by a readily-seen character, namely, the softer 

 parts of the compound animal invest and enclose the 

 harder parts, or skeleton. The coral of all this group is 

 therefore internal. The precious coral of commerce is 

 the skeleton of one of these Zoophytes ; and so is the 

 Gorgonia fldbellum, or Venus's Fan, a well-known West 

 Indian species which forms a beautiful network, strength- 



