160 CLASS IV. 



de Duvernoy (Synapta Duvernced), Ann. des Sc. Nat. 2e Sdrie xvn. Zool. 

 pp. JQ 03, PI. 2 5. Respiration is effected in the abdominal cavity, 

 into which the water passes by five apertures between the tentacles. The 

 booklets, shaped like anchors, one-tenth millim. in length and less, are set 

 on oval eminences of the skin, which are visible under the microscope alone. 

 Other similar eminences are covered with cells which can evolve an 

 extremely fine thread (nettle-organ ?). These animals appear to endure 

 wounding and extreme mutilation without being destroyed. 



Note. Ought the genus Haplodactyla GRUBE to be placed here ? 

 Tentacles cylindrical, simple. The author of the genus says nothing 

 about feet. Five respiratory organs, laciniate, sub-arborescent. GRUBE 

 ii. p. 42. 



Molpadia Cuv. Body tending to cylindrical or sub-pentagonal, 

 coriaceous, attenuated backwards. Tentacles short, cylindrical, 

 simple. Mouth armed with an apparatus of calcareous particles. 



Sp. Molopadia kolotkurioides Cuv. ; Molop. musculus EJSSO, Europ. merid. 

 Tom. v. figs. 31, 32. Comp. Cov. R. Ani., in. p. 241, BLAINV. Man. 

 d'Aclinol. p. 651. 



Family VI. Sipunculacea. Body cylindrical, elongate. No 

 calcareous ring around the oesophagus. Mouth provided with 

 a retractile proboscis. 



Sipunculus L. Body round, elongate, annulate. A papillated 

 retractile proboscis, with incised tentacular border or coronet of 

 simple tentacles surrounding the mouth. Anus a lateral aperture 

 of the body, situated towards the anterior part. 



Sp, Sipunculus nudus L., Syrinx BOHADSCH, de quibusd. animal, marin. 

 Tab. vn. fig. 6, 7, FORBES Brit. Starf. p. 245, LEUCKAKT Breves anim-alium 

 quorundam Descriptiones, Heidelbergae, 1828, 4to. fig. 3, and especially 

 GRUBE in MUELLER'S Archiv. 1837, Tab. x. fig. i ; in the seas of Europe, 

 especially the Mediterranean. This animal can attain a length of more 

 than one foot, exclusive of the proboscis, which is usually retracted. It is 

 very contractile and sometimes shortens itself one-half. Longitudinal and 

 circular bundles of muscle, visible through the skin, give it a latticed 

 appearance. The intestinal canal is very long, making two bends back- 

 wards and forwards ; the last ascending portion is wound spirally round the 

 preceding piece. Two brown vesicles, connected with the propagation, 

 terminate with fine apertures before and by the side of the anus. The 

 nervous system presents two rings round the oesophagus, and a cord 

 running on the abdominal surface, that gives off numerous branches, and is 

 surrounded by a blood-vessel as by an envelope ; see KROHN in MUELLER'S 

 Archiv. 1839, s. 348. From this species Lumbricus phaUoldes PALL. 

 Spicileg. Zool. X. Tab. I. f. 8, seems not to differ. Sipunculus cdulis, 

 Lumbr. edulis PALL. ib. fig. 7, is a species eaten by the Chinese. 



