1^93.] NATURAL SCIENCES OF PHILADELPHIA. 427 



Watauga Co., North Carolina, and by Mr. P. P. Calvert in 



Delaware Co., Penna. 



B. philadelphica Leidy. Astacobdella pliiladelphica Leidy, Pro. Acad. Nat. 

 Sci. Phila,, 1851, p. 209, Verrill, Rep. U. 8. ( lorn. Fisheries for 1872-73, p. 688. 



Fig. 4a, Plate XII, shows the external outlines of the body, and the 

 alimentary canal of a moderately sized living adult, x23. Figs. 4b 

 and c represents the dorsal, and 4d the ventral jaw, xlOO. Fig. 4c, 

 cocoon, x45. 



Dr. Leidy's description is here reproduced ' ' Body whitish, trans- 

 lucent; sides nearly parallel, a little broader posteriorly, sixteen 

 alternately broad and narrow segments exclusive of head and 

 posterior end. Head campanulate, terminated by a circular or 

 elliptical crenated lip, fringed with very minute stiff hairs, one two- 

 thousandth of an inch long. Acetabulum circular, one-sixth or 

 one- fourth of a line in diameter ; mouth elliptical. Dental plates 

 brown, nearly equal, forming an isosceles triangle, with the base 

 longest and attached apex of superior plate ending in a sharp conical 

 point ; with several very minute denticulations on each side, apex of 

 inferior plate bifurcated into two points, with two minute denticula- 

 tions on each side. Stomach capacious, nearly filling the anterior 

 eight alternately broad and narrow segments posterior to the head. 

 Anus dorsal, one-fifth of a line from the acetabulum. Generative 

 opening ventral, anterior to the anal aperture. Length, one to four 

 lines ; breadth, one-sixth to one-half of a line. Head, one-sixth to 

 one-half of a line long. Ovum attached by a pedicle, with an oper- 

 culum pointed at summit. From base of attachment to point of 

 opercle, one-fifth of a line. Length of body of ovum, one-sixth of a 

 line ; breadth, one-eighth of a line. 



"Habitat. — Found frequently in numbers from one to several 

 dozen upon any part of the exterior of the body of Astaeus baiioitii 

 Fab., but more especially upon the inferior surface and the 

 branchiae." 



The spermatheca is large, short- cylindrical, and curved; and the 

 penis-sac is cylindrical and possesses prominent atrial appendage. 

 The external openings of these and the ovaries are as usual. The 

 anterior nephridia terminate in very large transverse tubes which 

 open into a pulsatile vesicles ituated in the third segment. The other 

 anatomica characters are in no way remarkable. 



I have never found this species inhabiting the branchial chamber, 



