6 bulletin: museum of comparative zoology. 



into many folds to provide a greater surface for the glands that secrete the shell 

 of the cocoon (Fig. II). These glands are spoken of by lijima, but are not 

 figured by him. 



lua recent paper I (1896*, p. 1048) have discussed the sj'^nonymy of Leidy's 

 Procotyla fiuviatilis and expressed my belief in the identity of this species with 

 Dendrocalum lacteum ; upon the evidence presented above, I wish to emphasize 

 my conviction in this regard. The apparent differences between the forms are 

 in the American form the possible greater prominence of the frontal adhesive 

 organ, the more frequent variation in the number of the eyes, and the separation 

 of the seminal duct from the glandular part of the male sexual organ. The 

 first two of these diflerences, as I have endeavored to show, are differences in 

 degree only, and have no systematic value. The discrepancy between my 

 account of the male sexual organs and that of lijima alone stands as a real 

 difference. Although I can find no account of anything similar in other Tri- 

 clads, there are conditions comparable to these in the male organs of Polyclads 

 and Rhabdocoels (Lang, 1884, and Graff, 1882), and it is possible that this 

 detail has hitherto been overlooked in Triclads. 



Neither have I any hesitancy in placing under D. lacfeuvi Girard's D. pul- 

 cherrimum and D. superbum. The former differs, he says (1851, p. 265), from 

 D. lacteum " by having three pairs of eyes instead of two," while his D. svr 

 'pcrhum (1851», p. 2) " gleicht vielleicht noch mehr als die vorgehende Art 

 [D. pulcherrinium'] den D. lacteum, wovon es sicli unterscheidet durch kleinere 

 diinnere Gestalt, zwei Paar Augen, vorstehendere Horner und rothe oder milch 

 weiss Farbe." It is significant, too, that Leidy (1852'', p. 288) should have first 

 ascribed his Procotijla fiuviatilis to GhaxCCs, D. superhum (see Wood worth, 1896'', 

 p. 1048), and that Girard, in his recent extended monograph of North American 

 Turbellaria, makes no mention of these two old species of his. 



Planaria gonocephala DuGi:s. 



Figure 5. 



Planaria (jnnocephaln DuGi;s, 1830, p. 83. 



Planaria gonocephaloides Stimpson, 1857. p. 23. Diesing, 1862, p. 498. Silli- 



MAN, 1885, p. 69. 

 Dugesia gonocephaloides Girard, 1851, p. 265; 1851% p. 2 ; 1891, p. 188. 



Sides parallel, tapering gradually posteriorly to a rounded point. Anterior 

 end obtusely pointed, angular, the sides of the head making an angle of about 

 60°. Two angular cephalic appendages. In alcoholic material the auricles are 

 not prominent, scarcely showing at all in some specimens. Length of head 

 about ^ of the total length of the animal. Eyes two, in a plane joining the 

 apices of the auricles. Clear area surrounding the eyes sometimes elongated 

 in the antero-posterior direction. Color, dark reddish brown to grayish brown, 

 uniform. Posterior margins of auricular appendages free from pigment. 

 Length 9 to 15 mm., greatest breadth ^ to 2 mm. (Two alcoholic specimens, 

 which must have measured 20 mm. or more in length when alive.) 



