OF THE PKOTOZOA. TCHTHTDINA. 



381 



The latest researches, we have seen, on the Ichihydina are contained in a 

 paper by Dr. Max. Schiiltze {Mull. Archiv, 1853, p. 241), on ChcBtonotus and 

 Ichthydium, and on a new allied genus, Turbanella. In this communication 

 Schultze clearly shows that Glicetonotiis and IcJitliydmm are not Eotatoria, 

 whilst he admits Ptygura and Glenophora to be so. The leading and suffi- 

 cient reasons for sej)arating Ichthydium and Chcetonotus from Rotatoria are, 

 that they want the peculiar ciliary apparatus of that class have no retractile 

 rotary disk, no jointed tail-hke process, no water- vascular system with 

 vibratne tags, and no perceptible muscular and nervous system. The best 

 account of the organization we have of any of the Ichthydina is furnished by 

 Schultze's contribution above quoted, wherein he details that of TurhmieUa. 

 Of this we will present an abstract, but, before so doing, will preface a few 

 notes from Dujardin on Chcetonotus. This genus has a symmetrical elongated- 

 oblong body slightly contracted at its anterior thii'd, and having its posterior 

 half expanded ; covered on its upper or posterior surface by cilia or by cihated 

 scales ; terminated anteriorly by a rounded edge, near to which is a distinct 

 circular oral aperture ; and posteriorly ending by a bifurcate process. Some 

 long vibratile cilia are visible on the anterior half of the ventral surface ; and 

 Dujardin thought he discovered four or five minute papillae around the mouth. 

 This aperture he represents to lead into a long narrow oesophagus, which 

 abruptly ends in a wide intestine, that continues a straight course to the 

 posterior extremity, where an anal opening is probably placed. The Turba- 

 nella hyalina, of Schultze, has an elongated, rather compressed, colourless 

 body, from -gijth to ^th of an inch long, and j-^-yth to y-g-jj^^ broad. The head is 

 separated from the body by a constriction (XXXI. 28). Along the body, at 

 apparently regular distances, numerous bristle-like processes stand out at right 

 angles on each side. The posterior extremity is slightly contracted, and 

 divided into two comb-like flattened processes or lameUae, having an inter- 

 vening fossa, into which the anal aperture opens. A dorsal and ventral 

 surface are distinguishable, — the latter ciliated throughout, the former bare. 

 The head is entirely covered on its upper surface by fine cilia, besides which, 

 it has a circlet of larger ones around its middle. The cihated condition of 

 the under surface is displayed by a side or a transverse view of the animal. 

 The bristle-like processes on each side are growths from the integument, and 

 neither articulated nor separable (XXXI. 28, 30). The row is double on 

 either side ; the under setae from 20 to 25 in number ; the upper, only from 

 6 to 8 on a side. The latter are rather appendages of the dorsal surface, 

 and are, moreover, not at right angles like the others, but bent backward. 

 Each cutaneous process is terminated by a motionless cilium, equal to or ex- 

 ceeding it in length. The cuticle and its processes are soluble in a warm 

 solution of potash, and are not chitinous. 



The ahmentar}' canal passes straight through the middle of the body (XXX. 

 28, 29). The mouth, situated at the anterior extremity, is cii^ular, and sur- 

 rounded by a finely plicate or dentate margin ; it opens into a muscular 

 oesophagus, which very much resembles that of Anguillida, and terminates 

 below in the straight intestine. The oesophagus extends for the first fourth 

 of the length of the body ; and its muscular coat is so developed, that its canal 

 looks like a mere central Hue. Its muscles are annular. The tubular intes- 

 tine has, on the contrary, thin walls, in which numerous molecules and fat- 

 corpuscles are distinguishable, except, indeed, at its posterior conical termina- 

 tion. The intestine lies in a soft, finely-granular parenchyma. Xo water- 

 vascular apparatus with vibratile tags exists. At the posterior thii^d of the 

 body, on the dorsal surface of the intestine, a large ovary is placed, and in 

 front of it a veiy much smaller testis. Both glands present a mulberry- 



