of a few Armelids. 2 H 



liov4n were probably not in a healthy condition ; and as he him- 

 self 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 

 frequently been observed in our own larvse; and those thus show- 

 ing this apparent division (succeeding a stage where nothing of 

 the sort existed) invariably died soon afterwards, as was the case 

 with Loven's young Annelids. 



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

 pearance 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 contrac- 

 tion. In the present stage (fig. 4) we find otherwise no striking 

 difference from the previous one; the posterior part is some- 

 what more elongated, and we have the lines of ventral and dorsal 

 spots increased in number. With the growth of the larvse the 

 pigment spots of the body become suialler 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 articulations become more 

 distinct, the digestive cavity narrower; and the disproportion in 

 width between the oral disk and the diameter of the body at- 

 tains its maximum in the present stage; the anal ring has be- 

 come 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 (/) (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, with 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 accompanied 

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

 so much out of proportion as to give the larva the hammer- 

 shape it possessed before ; the part of the disk anterior to the 

 vibratile ring has somewhat elongated; the mouth (m) when 

 seen from the ventral side (fig. 8) appears quadrangular with 

 rounded edges ; it is situated close behind the anterior vibratile 

 chord, and edged on the posterior extremity with a row of large 

 pigment-cells. 

 . We now come to a series of changes plainly showing the 



