404 History of the Hairy -backed Animalcules. 



merits twelve. The first segment of the body is united to the 

 second by a simple intersection ; all the rest are separated by 

 a horny arch very distinct, presenting three articulations on 

 the plane or ventral face, viz., one answering to the axis, and 

 two lateral, between the edge and the middle. Each segment 

 encloses the next, and appears laterally armed with two points 

 or spines imbedded in the rear. It is covered, or simply bor- 

 dered with cilia, extremely fine, not vibratile, and very difficult 

 to perceive. 



Under the first or the second segment, according to the 

 state of retraction of the trunk, we perceive in the interior two 

 red oculiform specks, which pertain to the retractile and pro- 

 tractile portion of the digestive apparatus. To the extremity 

 of this retractile portion extends the oesophagus, longitudinally 

 plaited in the interior, and furnished in front with a coronet of 

 lobes, or teeth, which represent the mouth. The membranous 

 and plaited tube of the oesophagus is covered by a thick mus- 

 cular layer (couche), forming a cylinder 0*035 mm. wide, and 

 0"092 mm. long, which occupies the 3rd, 4th, and 5th segments 

 of the body, and which, swollen in the middle, takes the form 

 of the pharyngeal bulb of some worms. The stomach, which 

 succeeds, is cylindrical, 0*040 mm. wide, 0'17 mm. long, and 

 contracts itself from the front backward by successive waves : 

 it is invested with a brownish floccose layer, which appears to 

 represent a liver. Finally, a slenderer portion of the intestine 

 occupies the tenth segment, and terminates between the two 

 caudal plates. 



M. Dujardin has since found it, on repeated occasions, in 

 sea-water, on oyster shells, etc., always with the same form and 

 characters, without ova or genital organs. " If I had not seen 

 it," he remarks, " always alike in vessels preserved more than 

 a year, I might have supposed it the larva of some animal that 

 had escaped my researches. Incomplete, however, as are my 

 observations, after having vainly sought to add to them through 

 ten years, I believe that thoy suffice to show. a type differing 

 from those of the Helminthes acanthocephales, the Systolides 

 • or Rotifera, the Knfornostraca Copcpoda, and the Sipuncles, and 

 a1 tin.- Bame time offering points of resemblance to each of these. 

 It is ;i ion of Oopepode, without feet, with the mouth of a 

 Svpvmcuhts, and fche neck of a Echinorhynohus, and a muscular 

 oesophagus like those of the Systolides (Kotil'rra), the Tardi- 

 grades, and the Nematoid Helminthes." 



G-enus VI. — Tai'Hkocami'a (Ooshc) . 



Body articulate, destitute of hair ; posterior extremity 

 forked ; mouth a mastax, with mallei and incus,, which are 

 incurved. 



