2 BULLETIN OF THE 



"P. gracilis, nigricans, lateribus parallelis, postero acuto abrupte, 

 plerumque antico recto ; oculis duobus. Long. 9 lin., lat. 1 lin. Habitat 

 in foDtis Pennsylvanise. 



" Description. Oblong, limaceform, naked, convex superiorly, flat 

 inferiorly, very contractile ; sides ordinarily parallel, convex when the 

 animal is in a contracted state, convergent anteriorly when elongated ; 

 anterior extremity with a lateral triangular auricular appendage, straight 

 in front, by contraction becoming convex or concave ; posterior extremity 

 abruptly pointed ; ocelli two, anterior, composed of an oblong, semi- 

 transparent (nervous ?) mass with an intensely black dot of pigmentum 

 at the internal posterior part ; ventral apertures two ; oral aperture a 

 little less than one third the length of the body from the posterior 

 extremity. Color black or iron gray, and in some younger specimens 

 latericeous." 



I have quoted Leidy's description in full, because it seems to me that 

 the first description of so striking and aberrant a species is of uncommon 

 interest. 



It is noteworthy, that, notwithstanding the faithfulness of the descrip- 

 tion, and the remarkable peculiarities of the worm, no mention of the 

 species has been made for over forty years. It is also strange that 

 Girard should have been ignorant of the existence of Leidy's paper, for 

 in his list of North American fresh-water Planariaj ('51, p. 2G4) he 

 uses the name proposed by Haldeman, " Planaria gracilis," and says 

 that it is " common about Cambridge in pools and rivulets." Ho 

 adds, in a note, " Planaria gracilis and very likely Planaria tigrina 

 will not remain in the genus Planaria as soon as we shall know their 

 internal structure." In a subsequent paper ('51 a , p. 2), "Die Plana- 

 rien und Nemertinen Xord-Amerikas," the species is described under 

 the name given to it by Leidy, but no mention is made of the most 

 Btriking characteristic discovered by that observer, — the multiplicity 

 of the pharynges. 



The structural peculiarities of Phagocata were not simply ignored, 

 they- were even denied by no less an authority than von Siebold, who 

 explained the " proboscides " of Leidy as so many processes from the 

 lip of one normal pharynx. After quoting the description, he says 

 ('50, p. 389) : " T)as erwachsene Thier soil 23 Riissel haben, die es beim 

 Fressen alle hervorstreckt ; Ref. vermuthet, dass der Riissel eine trich- 

 terformige ausgezackte Miindung besitzt, und dass die beweglichen Fort- 

 satze des Riisselrandes fur ebenso viele einzelne Riissel gehalten worden 

 sind." 



