APPENDIX. 335 



Clitellio arenarius resides in places similar to Scenuris lineata, and 

 is equally common. When thrown into fresh water it is evidently- 

 pained, and soon dies. Cuvier has placed it in a section of his genus 

 Nais (Reg. Anim. iii. p. 212), but the propriety of this collocation 

 may be doubted ; and it will be better to retain the Mlillerian name 

 until the allied species, several of which have not yet been described 

 by any one, are better known. 



The spinules are very short, not half the diameter of the body, 

 and apparently entirely retractile ; they are colourless, curved like an 

 italic/, and resemble those of the common earthworm, being propor- 

 tionably stout. There are two only in the feet of the few anterior 

 segments, and three or four where most developed. 



Valla ciliata (page 68). 



Ilab. " It lurks constantly in the sand of the shore at about half 

 tide, whence the head is protruded, waving to and fro." — Daly ell. 

 This worm is found under stones, between tide-marks, in a wet 

 sand mixed with a little clay. It often lies fully extended, and it 

 moves forwards and backwards with equal ease*. When crawling 

 it can return upon itself, when the reverted anterior half lies parallel 

 with the posterior, and the two extremities move in opposite direc- 

 tions. It is very contractile, and frequently collects a portion of the 

 body into partial knots or swellings, and will again extend itself to a 

 great length, until it becomes as slender as sewing- thread. Its 

 red colour is very generally diffused, and to the naked eye no vessels 

 are visible ; but when placed under the magnifier and carefully 

 observed, the blood may be seen propelled to and fro through vessels, 

 one of which runs along each side of the intestine. The blood is 

 grumous, and nothing can be more irregular than its course, now 

 driven in one direction, then in the opposite, and then again settling 

 at rest ; for its motion seems to be dependent on the motions of the 

 body and the extension of the rings. The intestine is, as usual, 

 large, and deeply constricted at every joint ; it is usually filled with 

 earthy matter, and, when this is pressed out, it still appears dusky, 

 and somewhat reticulated in a very minute manner. I have never 

 seen any specimens with a belt, such as we see in the common earth- 

 worm. The number of tufts of bristles is hard to be correctly ascer- 

 tained, but there appear to be four on each segment ; and towards 

 the middle and posterior part of the body they issue from a very 

 evident cordate or roundish tubercle, which is not obvious on the 

 anterior segments. 



Miiller says that his Lumhricus cilia tus is only 9 lines in length, 

 but he had never seen a living specimen. It was sent to him from 

 the shores of Norway. 



* " In crawling, the segments enlarged at the place of their union ; and it is 

 a pecuUar feature, that a kind of intumescence appeared at intervals as the body 

 advanced, the portion thus enlarged being vivid red, while the vicinity became 

 pale, and this intumescence was transmitted along the body." — Dalyell. 



