NATURAL SCIENCES OF PHILADELPHIA. 89 



Aug. 2d, 1870. 

 Mr. Vaux, Vice-President, in the Chair. 

 Twelve members present. 



Prof. Leidy exhibited in a vessel of water, numerous living specimens 

 of a leech, which he said was abundant in the vicinity of Philadelphia, 

 but appears to be an undescribed species. He had first observed h in a pond, 

 on the Delaware, near Beverly, Burlington Co., N. J., from which he obtained 

 the largest specimens. It was found especially beneath half-submerged dead 

 limbs of trees, sometimes between the bark and wood, and in crevices and 

 holes of the latter made by insects. It was also found in the Delaware and 

 Schuylkill rivers near shore, beneath stones. In ditches below the city, and 

 communicating with the rivers mentioned, smaller leeches, apparently the 

 young of the same, were frequent between the leave sheaths of submerged 

 stems of aquatic plants, such as Zizania aquatica, Sdrpus fluviatilis, Sagitlaria, 

 Sparganium, &c. When disturbed, the animal receded from its position of 

 rest, and swam rapidly like the ordinary medicinal leech, JJirudo decora. It 

 appears to belong to a different genus from the latter, and approaches most in 

 character Nephelis, though it even exhibits points of difference from this as 

 ordinarily described. The more mature animal from the Beverly pond may 

 thus be characterized : 



Body elongated, flattened cylindroid, narrowing anteriorly, smooth, indis- 

 tinctly annulated, margin acute, above blackish olivaceous, below translucent 

 grayish, with a more or less reddish tinge due to the blood. No strise or 

 markings visible beneath, and the annuli in this position scarcely perceptible. 

 Annuli about 9S, above minutely punctated with yellowish olivaceous or 

 dusky whitish, and narrowly defined by the same hue. Head continous with 

 the body, obtuse. Mouth large, obliquely terminal, subbilabiate ; lower lip 

 crenulate. Jaws three rudimental folds without teeth. (Esophagus capacious, 

 with three longitudinal folds. Intestine simple. Anus dorsal, conspicuous, 

 in the penultimate annulus. Eyes six ; anterior pair largest and approxima- 

 ted: second pair in second annulus corresponding with the lower lip ; third 

 pair smallest, more deeply situated than the others, and placed slightly exter- 

 nal and posterior to the second pair. Acetabulum terminal, inferior, circular, 

 nearly as wide as the body. The larger male aperture conspicuous, ami 

 situated about one-fifth of the length of the body from the head ; the smaller 

 female aperture scarcely visible, and situated two or three annuli back of the 

 former. Length to 2J inches by two lines wide ; by contraction becoming 

 shorter and wider. 



Smaller specimens, from half an inch to an inch in length, from the ditches 

 communicating with the Delaware and Schuylkill Rivers, and from the latter, 

 agree in form and constitution with the preceding, having the same number 

 of annuli to the body, and the same number and disposition of the eyes. The 

 color is translucent pale indian-red, passing into darker shades and without 

 the colored punctse. Some young pale individuals exhibit a tew scattered 

 minute black punctaj down the back, due to single pigment cells, but mostly 

 these are absent. Intermediate sized individuals from the Delaware and 

 Schuylkill exhibit a gradation of character between the two forms indicated. 

 Further, numerous young from the ditches, kept in an aquarium for the Lasl 

 month, have gradually assumed the appearance of the more mature animal as 

 first described. 



Nephelis vulgaris of Europe has eight eyes ; and the generative apertures are 

 included between the 34th and 38th annuli. In the species above described I 

 could detect but six eyes, and the annuli at the fore part of the body are too 

 indistinctly defined to determine the exact relative position of the generative 

 apertures. 



The new species of Xephelis I would propose to name N. PUNCTATA. 



1870.] 



