51 INTRODUCTION TO ZOOLOGY. 



ones iii largo holes ; and their purple spines and regular forms 

 presented a most beautiful appearance studding the bottoms 

 of the gray limestone rock-pools." 



The individuals of the fifth family (Holothuridai) are not 

 likely to attract the notice of the casual observer, and are of 

 comparatively rare occurrence even to the naturalist. The 

 English term, Sea-cucumbers (Fig. 35), gives some idea of 

 their general form. In them the spines have disappeared; 

 but, as the covering of the body is soft, they can move by tho 



Fig. 35. HOLOTHUKIA. 



extension or contraction of its parts, as worms do ; and, like 

 the Sea-urchins, they continue to employ the aid of stickers. 

 They are remarkable for their power of casting off and of 

 reproducing parts that would seem the most essential. Sir 

 J. G. Dalyell* has known them to lose "the tcntacula, with 

 the cylinder (dental apparatus), mouth, oesophagus, lower 

 intestinal parts, and the ovarium, separating from within, and 

 leaving the body an empty sac behind. Yet in three or four 

 months, all the lost parts are regenerated." 



Mr. Forbes states, " It is this animal which the Malays 

 of the Oriental Isles seek so diligently for the supply of the 

 China market, where it obtains a good price when well pre- 

 served. It is employed by the Chinese in the preparation of 

 nutritious soups, in common with an esculent sea- weed, Sharks' 

 fins, edible birds' nests, and other materials, affording much 

 jelly. Jaeger says the intestines arc extracted, the animal 

 then boiled in sea-water, and dried in smoke." 



A species found off the coast of Cornwall, and first described 



* Paper read at Glasgow Meeting (1840) of British Association. 



