The Microscope. 35 



they have also become developed, and finally they have appeared in 

 a small collection of Lemna, sent to the vpriter for another purpose 

 by Mr. H. E. Valentine, of Boston, and left standing on the table for 

 several weeks. They therefore seem to prefer the proximity of 

 decaying vegetation, and their habitat appears to be in favorable 

 situations along the entire Eastern coast, south of and including 

 Massachusetts. 



The food consists chiefly of the softened and decaying leaflets 

 and other parts of the plants, together with the fine, granular debris 

 which collects at the bottom of the water. These matters are seized 

 by a snapping motion of the mouth and lower lip. Animal food 

 appears to be taken by accident only; it consists chiefly of Rhizo- 

 pods. 



The only American species of uSolosoma, with the exception of 

 the one here referred to, was discovered by Dr. Joseph Leidy, and 

 was described by him in the Journal of the Academy of Natural 

 Sciences, of Philadelphia, II, 2, November, 1850.* He named it 

 jEolosoma venustum, having obtained it among Confervse, upon which 

 it feeds, in fi'esh water ditches near Philadelphia. Upon the present 

 form I propose to bestow the specific name distichum. 



Two characteristics of the genus uSSolosoma are the absence of 

 the podal spines, so common in certain Oligochfeta, and the presence 

 of numerous, scattered, bright red spots which, at first glance, 

 appear to be superficial, but are, on the contrary, embedded within 

 the tegument. In JE. venustum, Dr. Leidy states that "the red 

 globules variegating the posterior part of the body appear to be 

 colored nuclei in the muscular bands of the tegument." The same 

 appearance obtains with the entire body of jE. distichum, where, in 

 some instances, the transverse muscular bands become very distinct, 

 and the red spots correspondingly conspicuous. 



The body is colorless, depressed, broad, changeable in form, and 

 attractively variegated by these large, irregular, red spots distinctive 

 of the genus. The articulations vary in number from eight to 

 twelve, all of which, except the first, or oral one, are furnished with 

 apparently four fascicles of bristles, two on each side (one dorso- 

 lateral and one ventro-lateral), but this arrangement is apparent 

 only. The two fascicles on each setigerous segment, (one on each 

 side) are divided into two somewhat widely separated parts, each 

 articulation therefore, except the first, seeming to have four fascicles 



♦Since this was written Prof. F. W. Cragin has described two additional forms from 

 Kansas, naming them ^. Leidyi and JE. Stokesii respectively. (Bui. Washburn Collei/e 

 Laboratory;!!. 2, Oct. 1887.) 



