1 86 ECHINODERMATA. PART in. 



independent fragments, each of which keeps moving for 

 a time, and ultimately becomes a perfect animal like its 

 parent. Specimens of this Synapta hare been found on 

 the southern coasts of England and in the West of 

 Scotland, but the genus is rare, although containing 

 several species- in the British seas ; it is more common 

 in the Adriatic; but they cannot be compared, as to 

 size, with the great Synapta of Celebes, which is some- 

 times a yard in length, and is known among the natives 

 as the Sea Serpent. 



The calcareous particles imbedded in the skin of the 

 allied genus Chirodota are wheel-shaped when viewed 



with a microscope (fig. 145) . 

 One species is British, but 

 they are mostly inhabitants 

 of warm seas. In Chirodota 

 violacea, a Mediterranean 

 species, the skin is full of 



Fig. 145. Whed-UkeFlates of Chirodota g roups Q f broad thin h ya- 



line wheels lying upon one 



another and connected by a fine thread. The wheels 

 have five or six flat radiating spokes. 1 The wheels are 

 exceedingly small in the Chirodota Isevis, and are ar- 

 ranged in groups ; in the C. myriotrochus they are im- 

 bedded in myriads, as the name implies. 



Echinodermata Sipunculidce. 



The Sipunculidse, which form the last order of the 

 Echinoderms, consist of several genera of marine worm- 

 shaped animals which burrow in the sand, and form a 

 link between the Holothuridse and the true sea- worms. 

 They have no calcareous particles in their flexible skins, 

 nor have they any tubular feet, or special respiratory 

 organs, but a vascular liquid is kept in motion in the 



1 ' The Microscope,' by Dr. Carpenter. 



