Dr. F. Miiller on Lumbricus corethrurus. 15 



This short description will suffice to give a pretty good idea 

 of our Earth-worm, and at least allow it to be easily distinguished 

 from the other species hitherto described. Although the ar- 

 rangement and form of the bristles are usually regarded as essen- 

 tial generic characters of the Earth-worms, and the present worm, 

 which is so peculiar in this respect, appears imperiously to demand 

 the formation of a new genus, I have been unable, especially 

 on account of the regularly bristled young, to determine upon 

 taking this course, the rather as there is no material anatomical 

 or physiological peculiarity to justify this separation, as is the 

 case for example in Euaxes and Criodulus, the latter of which is 

 so deserving of a minute investigation. Perhaps some such 

 point may appear to exist on the further investigation of a pecu- 

 liarity, which has induced me to bring this insignificant animal 

 before the zoological public. In almost all the larger specimens, 

 one is struck immediately by a small spot about the end of the 

 third quarter of the body, which appears of a more vivid red and 

 as if inflamed ; on the dorsal surface at this point the delicate 

 skin often appears to be inflated, and as it were to form a small 

 sac [Bruchsack). In specimens killed in spirits this spot looks 

 like a second but much smaller clitellus, as it is sharply sepa- 

 rated and rises a little above the segments before and behind it, 

 probably because in the contraction of the body the weaker skin 

 and muscular layer present less resistance here. If this spot, 

 which I have not missed on any of the very numerous adult 

 animals which I have examined for it, be examined with the lens, 

 it is found to be composed of from 5 to 10, more or less distinctly 

 separated, narrow segments, without bristles, and according to 

 all appearance newly formed. 



My first thought on seeing this new formation, was of the 

 commencement of a transverse division; but, then, specimens 

 produced by such a transverse division should have occurred, and 

 these would have been destitute either of a proper anterior ex- 

 tremity or of the brush-like tail ; for these, however, I have sought 

 in vain. On counting the segments in nine specimens there 

 proved to be nearly the same number of segments (namely 110) 

 between the clitellus and this spot; the inconsiderable differences 

 may be due to mistakes in counting. On the other hand, the 

 number of segments behind the spot varied from 60 to nearly 

 double that number. This spot might therefore possibly be a 

 place for the formation of new caudal segments. Observations 

 continued through all seasons may perhaps give us certainty 

 even without a microscope. 



Itajahy, June, 1856. 



