272 Transactions of the Society. 



and communicated to me by Dr. K. M. Levander. This arrange- 

 ment of the mouth, auricles, vibratile cilia, and frontal styles is 

 common to all Synchaetae. Another peculiarity of all species of 

 this genus, which has not been described before, is the single row 

 of very fine short setae which surround the shield-shaped mouth, 

 all curving over the opening and forming a dome-shaped screen 

 through which all food-particles must pass before reaching the 

 mouth. In some species some of these stiff fine hairs can just be 

 perceived at the extreme front from a dorsal view, but the real 

 shape and structure of this screen can only be seen well from a 

 good front view with a high power. 



There are other bundles of sense-hairs on the front of the head 

 which vary in different species and are described in their respective 

 places. 



Unlike what obtains in most other Eotifers, it appears that in 

 no Synchaeta do the lateral canals and flame-ceils (vibratile tags) 

 extend much beyond the anterior end of the gastric glands. The 

 lateral canals lie close to the walls of the stomach on each side, if 

 they are not actually fixed to them by connective tissue threads ; 

 near the gastric glands they make a convolution to which two 

 flame-cells are usually attached, and send on each side a single 

 short branch forward which is attached to the body-wall by a fine 

 thread, and terminates in one or two flame-cells. Two more flame- 

 cells are situated on the branch lying near the middle of the 

 stomach on each side. In no case have I observed a lateral canal 

 or flame-cell in the head of a Synchaeta. Posteriorly the lateral 

 canals usually make a loop in the wall of the contractile vesicle 

 before opening into it. 



In all Synchaetae the muscular bands, retractors of the head and 

 foot, are very narrow and finely striated. 



The brain-sac is large and usually lobed, very transparent and 

 not readily seen ; it carries the cervical eye, which is a spherical 

 vesicle filled with granules which may be all red or partly red and 

 partly white. In the first case the eye appears spherical as in S. 

 pcctinata and stylata ; in the other cases, as in S. tremula, oblonga, 

 tavina, &c, it appears more or less completely divided into closely 

 apposed halves, which may be unequal in size. In two species, 

 i.e. S. triophthalma and littoralis, there is a very fine double canal 

 connecting the cervical eye with two red eye-spots in the front part 

 of the head ; the canals are filled with numerous very fine red 

 granules. I have observed similar canals containing a few scat- 

 tered red granules occasionally in S. tremula and oblonga. The 

 colour of the eyes of Synchaeta is usually red, sometimes with a 

 tinge towards violet. The red may occasionally be so deep as to 

 appear black by transmitted light. These eyes enable the Syn- 

 chaetae to perceive light, and they quickly collect to the light side 

 of a small aquarium, but there is no evidence that they can see 



