On the IToung Stages of a few Annelids. 313 



frequently been observed in our own larvae, and those thus 

 showing this apparent division (succeeding a stage where 

 nothing of the sort existed) invariably died soon afterwards, as 

 was the case with Lovdn's young Annelids. 



As far as I could ascertain, a number of rings make their 

 appearance at once (Fig. 4), and are the more distinct the 

 nearer they are placed to the mouth ; they appear at first like 

 faint transverse lines, readily mistaken for furrows formed by 

 contraction. In the present stage, Fig. 4, we find otherwise no 

 striking difference from the previous one ; the posterior part is 

 somewhat more elongated, and we have the lines of ventral and 

 dorsal spots increased in number. With the growth of the 

 larva? the pigment spots of the body become smaller and more 

 irregularly scattered (Fig. 5), while there is no diminution as 

 yet in the size and brilliancy of the pigment spots of the oral 

 and anal vibratile rings. As the body elongates the articula- 

 tions become more distinct, the digestive cavity narrower, and 

 the disproportion in width between the oral disk and the dia- 

 meter of the body attains its maximum in the present stage; 

 the anal ring has become somewhat more prominent than in the 

 previous stage. The part of the body, as yet not divided into 

 rings, can be plainly seen in Fig. 6 placed next to the anus ; 

 the whole of the stomach is lined with powerful vibratile cilia, 

 particularly well developed at the opening of the oesophagus 

 into the stomach, and at the beginning of the intestine, c. 

 Fig. 6. 



There appear at the stage of Fig. 4, in front of the eyes, two 

 small tentacles (t) (as observed by Loven), placed nearly at the 

 extremity of the young worm. The body of the larva now 

 takes a rapid development, and in the stages next represented 

 here, Fig. 7 (which w 7 ith the previous stage, Fig. 5, are phases 

 not fully described by Loven), we find as many as forty-three 

 rings, and the pigment spots of the body more numerous than 

 in previous stages. The lengthening of the body is accompa- 

 nied by a decrease in the relative size of the anterior disk, no 



