8 BULLETIN: MUSEUM OF COMPARATIVE ZOOLOGY. 



posterior intestinal trunks, a condition that was present in fifty out of seventy- 

 one specimens examined. In place of the two posterior trunks of the intes- 

 tine, which exist in the ordinary Triclad type, there are often as many as three 

 parallel trunks on each side of the pharyngeal chamber (Fig. 7). The acces- 

 sory trunks either take their origin at the root of the phar\nix, like the two 

 normal posterior trunks, or exist as parallel branches of the latter, and 

 usually unite with it and with each other close to their posterior termina- 

 tions. I have never seen any anastomoses of the trunks of one side of the 

 body wdth those of the other side, as in D. lacteiim. When accessory trunks 

 are present, they bear no lateral branches, but in place of these possess 

 slight projections or buds, the lateral branches probably being suppressed 

 through lack of space. The anterior portion of the intestinal tract, in almost 

 every case where the specimens were not too heavily pigmented to be studied, 

 exhibited anastomoses of the lateral branches, the intestine in some instances 

 existing as a network (Fig. 7). (See under D. lacteum, ante, p. 2.) Unfortu- 

 nately, I cjm say nothing in. regard to the sexuid organs of this species. In 

 over one hundred individuals examined, not one was sexually mature or showed 

 any signs of sexual organs. 



Girard (1893, p. 181) describes three varieties of Dugesia maculata. The 

 description he gives of his first variety, var. a, agrees closely ■ndth the form 

 described above in size and shape, in color, in the frequent occurrence of 

 the light median streak, in the greater length of the auricular appendages, 

 and the more pointed shape of these and the head end. His Figure 56 also 

 shows a third posterior trunk of the intestine, but median in position and 

 anastomosing with the lateral trunks. There can be little doubt that var. a 

 of Girard's D. maculata and P. dorotocepliala are the same. 



There is also a striking resemblance between F. dorotocepliala and Kennel's 

 figure of P. aurita (1888, Fig. 3). 



. Planaria maculata Leidt. 



Figures 2, 3. 



Planaria maculata Leidt, 1848, p. 251 ; 1848% p. 78; 1852, p. 225 ; 1852*, p. 289 ; 

 1885, p. 50. DiESixG, 1850, Vol. I. p. 205 ; 1862, p. 499. Stimpson, 1857, 

 p. 23. SiLLiMAN, 1885, p. 70. Woodworth, 1896, p. 94 ; 1896% p. 240. 



Dugesia maculata Giraed, 1851, p. 264 ; 1851% p. 2 ; 1893, p. 181, var, b and c. 



Planaria tigrina Girard, 1851, p. 264; 1851% p. 2 ; 1891, p. 179. 



Anterior end pointed, sides of the head making an angle of about 60°. Two 

 angular cephalic appendages. Length of head about -^^ the total length of the 

 animal. Eyes two. Sides parallel to about f of the total length from the 

 anterior end, then tapering gradually to a rounded point. Color, blackish to 

 purplish by reflected light ; blackish or gray by transmitted light. In smaller 

 young specimens, the pigment occurs in isolated patches and spots ; in older 

 specimens the pigment patches become more confluent, chiefly in the median 

 region leaving clear irregular areas scattered over the surface of the animal. 



