148 



HARDWICKE'S SCIENCE-GOSSIP. 



right round the body, like the lines of latitude and 

 longitude on a globe. From these depressions the 

 cilia appear to arise and there is also a small tuft of 

 cilia at the anterior end, and one or two cilia spring 



It is interesting to note that this mode of asexual 

 reproduction is similar to that observed in some 

 Desmids {e.g. Cosmarium). 



25. Chcetojiotiis lams (Fig. 88) was placed by 



Fig. %l.—Coleps hirtus — 1 and 2 highly magnified; 3, dividing. 



from the posterior end, where there are three tiny 

 hooks easily overlooked from their minuteness ; they 

 probably are modified cilia. 



In the endosarc there are usually one or two round 

 green or brown bodies, perhaps the food swallowed 

 by this organism. There is also, often, a large, 



Fig. 88. — Chatonotus larus — 1, front view 2, side view ; m, 

 mouth ; is, gullet ; end, endosarc ; ect, ectosarc ; k. tail 

 process. (Highly magnified ) 



highly refractive, colourless body near the centre. 

 When fission takes place, the organism divides into 

 two equal halves by a transverse constriction, each 

 half thus separated developing a protoplasmic portion 

 devoid at first of cel'.-wall, but furnished with cilia. 



Ehrenberg among the Rotifera. Indeed its general 

 appearance is suggestive of a higher place than among 

 the Infusoria. Its size varies from about the seven 

 hundredth to the two hundredth of an inch. Like 

 Coleps, it is symmetrical, and the body is three or four 

 times longer than broad ; on the dorsal surface there 

 are long bristles pointed backwards, and on the ventral 

 or oral surface very minute cilia. It is an exceed- 

 ingly rapid swimmer, and darts along, head foremost, 

 so quickly that it is difficult to make out its structure. 

 The anterior region or head is marked with one or 

 two elevations, or tubercles, it is ciliated, and on the 

 under-surface a round mouth may be seen furnished 

 with movable lips. As the head moves about it is 

 " telescoped " into the neck in much the same manner 

 as is the head and tail of the Rotifer. The neck is 

 thick and long, furnished with cilia, it passes, almost 

 imperceptibly into a slightly broader body. At the 

 posterior extremity there are two short, pointed pro- 

 cesses, separated from each other by a short interval 

 covered with cilia. 



The outer layer of protoplasm is hyaline, and the 

 granular inner substance is very clearly marked off from 

 it. The mouth leads to a long oesophagus, traversing 

 the neck, with transversely striated walls, and this 

 ends in the inner substance. I have never discovered 

 the nucleus. The terms endosarc and ectosarc are 

 avoided, because it seems difficult to refer this very 

 interesting organism to its true place in the animal 

 kingdom ; if it be one of the ciliata, it is probably 

 the highest member of that series. 



26. Stylonichia mytdlus (Fig. S9) of Ehrenberg 

 (Kicrona mytdlus of Dujardin) is from the two hun- 

 dredth to the one hundreth of an inch long. It 

 is heterotrichous, the cilia being of very different 

 kinds. In the oral region, fringing the mouth, the 

 cilia form a comb ; posteriorly they are modified 

 into styles, two of these point outwards at an angle 

 with the body and a few between these point 

 directly backwards and arise from the under-surface. 



