312 On the Young Stages of a fevj Annelids. 



body, between the anal and anterior vibratile chords ; there is 

 besides a crescent-shaped row of spots along the posterior edge 

 of the month (m). The two jet-black eye-spots (e) on each side 

 of the summit of the disk are also found in onr larva (seen only 

 when facing the ventral or dorsal side, as in Fig. 7). The eyes 

 have a totally different appearance from the other pigment 

 spots found along the body and vibratile rings. They are ap- 

 parently connected with a nervous ganglion sending off deli- 

 cate branches to the anterior vibratile ring. The mouth opens 

 behind the anterior vibratile chord, leading into a well defined, 

 oesophagus communicating with a stomach, which is distinctly 

 separated at its posterior extremity from the intestine ; the 

 latter opens externally in the middle of the anal vibratile 

 chord, placed at the base of the anal ring; this is slightly coni- 

 cal, and projects somewhat beyond the vibratile chord. 



Loven distinctly states that the rings are formed immediately 

 at the base of the anterior disk, behind the mouth ; this is pro- 

 bably an error of observation, owing to the advanced period at 

 which the articulations first commence, or the rings are simply 

 folds due to contraction. He describes all the rings of his young 

 Larva (Loven, Fig. 2) as made up of four pieces, and represents 

 the same thing again in his Fig. 5. Nothing of the kind could 

 be seen in the formation of the rings in our larva (Figs. 4, 5). In 

 somewhat more advanced stages, after the first rings were dis- 

 tinctly developed, I had no difficulty in finding near the anal 

 ring a small part of the body of the worm in which the articu- 

 lations became more and more distinct as they were more dis- 

 tant from the anus (Fig. 6); showing beyond doubt that new 

 rings are formed between the anal rings and the older anterior 

 rings, as in other Annelid Larvse, and not immediately below 

 the disk near the mouth as stated by Loven. The larvae figured 

 by Loven were probably not in a healthy condition, and as he 

 himself mentions his inability to keep them beyond a few days, 

 it seems probable that the peculiar composition of the rings, of 

 four pieces, is simply due to contraction. The same thing has 



