INFTTSORIAL ANIMAT.CTTtES. 69 



(fig. 388) ; whilst the caf;cs of Flosmla/ria, (fig. 384) Tulicola/ria, (fig. 

 379) and Stephanoceros, (fig. 383) are loose and hyaline. 



These outer gelatinous and tubular sheaths, are clearly, products 

 from the animal, which secretes them, as the coral-animals do their 

 cells, or the mollusca their shells. (See Mclicerta and Tlate XXIII.) 



In the genus Clmtonotus^ Dujardin even denies the existence of a 

 proper integument, and ranks it with the Polygastrica. (For a 

 summary of the external processes of Rotatoria, see Section II.) 



In this class, a muscular system, subservient to the functions of 

 locomotion, nutrition, &c., is well developed, and the integuments 

 being transparent, its sti'ucture and disposition are distinctly visible 

 imder the microscope, without dissection. The principle muscular 

 member is a foot-like non- articulated process, situated on the ventral 

 surface of the posterior part of the body. This member is usually 

 called the tail ; but being situated anteriorly to the discharging orifice, 

 is not properly such. It has usually the faculty of being able to 

 slide one part within another, and recalls to the observer the move- 

 ment of the sliding tubes of an opera-glass, or telescope. Its 

 extremity is often so formed, that the creature can cause itself to 

 adhere to any substance, by probably producing an exhausted cavity 

 within the disc-like extremity, as do the leech and some parasitic 

 acari found on beetles. Sometimes the termination of this false foot 

 has two or more toe-like processes. By the construction of this 

 member, the creature is enabled to attach itself, while the anterior 

 part is moving about in search of provender, and likewise to employ 

 it as an instrument of progression, by alternately contracting and 

 elongating it, and fixing itself by it and the mouth, after the manner 

 of a leech. Muscles for moving the body, and the rotatoiy organs, 

 are mostly visible ; they are known by their thickening during con- 

 ti'action, and by dilating when elongated. 



"With reference to their arrangement, the muscles form two sets — 

 the one, annular, encompassing the body; the other, longitudinal. 

 The former are separated from each other by considerable intervals, 

 and give to the body the appearance of being divided into several 

 transverse segments. The longitudinal muscles arise from the in- 

 tegument, and proceed forward to be attached to the oesophageal bulb, 

 or to the rotaiy apparatus, or else backwards to the tail, with its 



