Sipunculus. RADIATA. ASTERIAD.E. 491 



Gen. MARSUPITES — Body, subglobose, covered by calca- 

 reous plates, united by simple sutures, destitute of filaments, 

 of which the dorsal central one is angular, surrounded by 

 a series of costal plates, admitting intercostals at their peri- 

 pheral angles, these giving insertion to the scapulae which 

 support the arms ; the oral disc covered by articulated 

 plates, with the mouth in the centre. 



1. M. ornatus — Plates of the body sixteen, radiated; arms dichotomous ; 



the plates covering the mouth, disposed in a proboscideal form Tortoise 



Fnerinite, Park. Org. Rem. ii. 225 — M. orn. Mill. Crin, 13G M. Milleri, 



Mant. Geol. 184. t. 16. f. 6 In Chalk. 



Gen. XIII. SIPUNCULUS— Mouth a retractile proboscis, 

 with a laciniated margin. Vent lateral, near which are the 

 orifices of the oviducts. The species burrow in the sand, 

 or in the cavities of old univalves. 



36. S. nudus. — Body of nearly equal thickness throughout, 

 longitudinally and transversely striated. 



Perm. Brit. Zool. iv. 36. t. xx. f. 10 English coast, frequent. 



37- S. saccatus. — Body covered with a loose skin, smooth, 



and globular at the extremity. 



Mont. Lin. Trans, vii. p. 75 — Teignmouth, Mr Martin. 



M. Cuvier conjectures that this may be merely the preceding species in a 

 state of decomposition. 



38. S. strombus. — Body nearly cylindrical, smooth before, 

 but verrucose behind the vent. 



Mont. Lin. Trans, vii. 75 — Inhabits the old shells of Rostellaria pes 

 Pelecani, Devon, Mont. 



The animal contracts by means of agglutinated sand, the aperture of its as- 

 sumed dwelling, leaving only a small round opening. Shells of the Denta- 

 lium, in the Frith of Forth, are frequently found contracted at the mouth in 

 this manner, but the species remains to be determined. 



Gen. XIV. PRIAPULUS.— Body lengthened, cylindrical, 

 the mouth terminal, with corneous teeth ; vent terminal, 

 with a projecting process covered with filaments. 



39. P. caudatus. — Head enlarged, with twenty-four rows of 



minute pointed processes. 



Holothuria priapus, Linn. Syst. i. 1091. Fab. Faun. Groen. 355. Mull. 

 Zool. Dan. t. xcvi. i. and t. cxxxv. 2. — Scottish seas. 



