M. R. Leuckart on the Young States of some Annelides, 261 



width. The next following segments certainly yield but little 

 to this in length, but the later ones from about the middle of the 

 body diminish rather rapidly to a considerable extent. On each 

 of these segments four pedal tubercles (fig. 3) may be distin- 

 guished (not two, as stated by Busch) ; two of them are dorsal 

 and two ventral, they are placed on the nearly perpendicular 

 lateral surfaces, and have the form of slight, but very distinctly 

 marked elevations. The bristles of the two pairs of pedal tuber- 

 cles are of difi^erent forms ; the dorsal tubercles contain edged 

 capillary bristles (fig. 4), the ventral ones on the contrary ex- 

 tended uncini, the ends of which (as shown in fig. 5) form two 

 unequally developed teeth. As is usually the case under such 

 circumstances, the capillary bristles are the longest. The num- 

 ber of bristles diminishes gradually towards the hinder extre- 

 mity ; on the anterior segments it amounts to six or seven, on 

 the posterior ones only to two or three. Above the dorsal pedal 

 tubercle there rises a slender cirrus, clothed with short cilia ; the 

 length of this is however constantly less than that of the bristles, 

 even in the anterior half of the body. 



The segments are further distinguished by the peculiar ciliary 

 lobes or combs described by Busch (figs. 2 & 3), which are 

 situated on the ventral surface and occupy about the middle of 

 the space between the ventral pedal tubercles and the median 

 line. The cilia of which these are composed agree in size and 

 development with the remains of the ciliary wreath, at least on 

 the anterior segments, but they gradually diminish considerably 

 both in size and number as we proceed backwards. In front 

 I not unfrequently counted twelve or even more hairs, standing 

 regularly close together in a transverse line ; on the hinder seg- 

 ments there were only from six to eight. The two first segments 

 of the body form an exception to this, as they are quite destitute 

 of these ciliary combs, but instead of them are covered on the 

 ventral surface with a uniform soft coat of cilia. 



The last segment of the body is destitute of bristles, but is 

 considerably broader and longer than the preceding rings. It 

 forms as it were an annular protuberance around the anus, and 

 is margined with a circle of powerful cilia. 



Of internal organs the intestinal canal alone could be distin- 

 guished ; it exhibits a very great development in our animal. 

 Its commencement forms an oesophagus, without a protrusible 

 proboscis or any armature; but with fleshy walls, which are 

 dilated on each side into tolerably wide caeca in the second, third 

 and fourth segments. In the fifth segment the stomach com- 

 mences; it contains a greatly developed, yellow glandular layer, 

 by which it is very clearly distinguished even at the first glance 

 from the oesophagus; although it appears otherwise to be only 



