160 CLASS Iv. 
de Duvernoy (Synapta Duvernea), Ann. des Sc. Nat. 2e Série xvit. Zool. 
pp. 19—93, Pl. 2—s. Respiration is effected in the abdominal cavity, 
into which the water passes by five apertures between the tentacles. The 
hooklets, 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 GruBeE 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 holothurioides Cuv.; Molop. musculus Risso, Europ. mérid. 
Tom. v. figs. 31, 32. Comp. Cuv. R. Ani., 1. p. 241, Buainv. Man. 
@ Actinol. p. 651. 
Family VI. Stpunculacea. Body cylindrical, elongate. No 
calcareous ring around the cesophagus. Mouth provided with 
a retractile proboscis. 
Stpunculus LL. 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. Stpunculus nudus L., Syrine Bowapscu, de quibusd. animal. marin, 
Tab. vii. fig. 6,7, Forbes Brit. Starf. p. 245, Leuckart Breves animalium 
quorundam Descriptiones, Heidelberge, 1828, 4to. fig. 3, and especially 
GRUBE in MUELLER’S Archiv. 1837, Tab. X. fig. 1 ; 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 cesophagus, 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 phalloides PAu. 
Spicileg. Zool. x. Tab. 1. f. 8, seems not to differ. Stpunculus edulis, 
Lumbr. edulis Paut. ib. fig. 7, is a species eaten by the Chinese. 
