FIELD AND FOREST. I37 



and Point Pelee Islands, as I did not have opportunity to observe 

 them as carefully as the others. It may be possible, and in fact is 

 quite probable that the summer residents vary with each season, so 

 that we might expect to note some change in the avi faunas each year. 



W. H. Ballou. 



W orms. — L um bricus Terrestris . 

 (Continued from page t2q, last issue.) 



The muscular system is comparatively simple. The fibres are longi- 

 tudinal and tranverse, or circular. The worm is not sheathed in 

 an unbroken sheet of muscle with apertures for the setae, generative 

 organs, &c, but the longitudinal fibres are collected into four, if not 

 five, distinct systems extending from end to end, the lines of separation 

 being the four double rows of bristles, with points of attachment at 

 the junction of the segments. Thus there is a long abdominal muscle 

 between the second and third series of setae ; a ventro-lateral on each 

 side, between the first and second, and the third and fourth ; and one, 

 if not two, dorso-lateral, between the first and fourth rows. The 

 circular bundles of fibres, above and outside the longitudinal, pass 

 around each segment, making as many annular muscles as there are 

 rings to the body. Each seta has two, also transverse and longitudi- 

 nal, the latter being below those of the same name for the purpose of 

 shortening the body, and frequently so intimately connected with each 

 other that they form but one, while the transverse bundles are below 

 and within. The setae are hooked into the muscles and so firmly 

 attached that the forcible extraction of a bristle generally brings with 

 it some torn fibres. The transverse muscles are especially interesting. 

 Each one — we are now looking' down on the inner abdominal surface 

 after the intestinal canal has been carefully removed — extends above 

 the long ventro-lateral muscle of the body, dips down and around its 

 two edges, passes down the inner side of the setae-bearing muscle, and 

 when about midway, enters the latter, within which its fibres are lost. 

 They do not cross the ventral median line, but connect the first double 

 row of setae with the second, and third with the fourth. They, as 

 well as each set of setigerous muscles are, as a rule, firmly fused 



