NATURAL SCIENCES OF PHILADELPHIA. 79 



is crenulate, usually with six shallow crenulations, and the animal 

 is devoid of chlorophyl. The former is usually the smaller, and 

 may be distinguished with the name of D. lobostoma ; the latter 

 may be named D. crenulata. 



In an old brick pond, on the grounds of Swarthraore College, 

 Delaware County, among Difflugia pyriformis, D. spiralis, D. 

 corona, D. acuminata, and others not yet determined, there occurs 

 an abundance of a large species, apparently undescribed. It is 

 sometimes the fourth of a line in length, and is compi'essed pyri- 

 form, but is quite variable in its relation of length to breadth, and 

 in the shape of the fundus of the shell. This is often trilobate, 

 but from the non-production of one or more or all the lobes, differs 

 in appearance in different individuals. The animal is filled with 

 chlorophyl grains, from which it might be named D. entochloris. 



Another large Difflugia, allied to D. lageniformis, is not unfre- 

 quent about Philadelphia. The shell is beautifully vase-like in 

 shape. It has an oval or sub-spherical body with a constricted 

 neck, and a recurved lip to the mouth. The body of the shell 

 opposite the mouth is acute and often acuminate. The animal 

 contains no chlorophj'l. One shell measured g- of a line long by 

 I" of a line broad; another measured ;^ of a line long by ^ of a 

 line broad. The species may be named D. amphora. 



A DifHugian, found in a spring on Darby Creek, is interesting, 

 from its transparency, whicli allows the structure of the animal to 

 be seen in all its details. The investment is membranous and 

 apparently structureless. The soft granular contents occupy 

 about one-half of the investment, and are connected with this by 

 long threads. The pseudopods are protruded in finger-like pi'o- 

 cesses. The form of the animal is compressed ovoid, with the 

 narrow pole truncate and forming the transversely oval mouth. 

 It is probably the species Difflugia /^g'a^a, described by Mr. Tatem, 

 of England. Its length is about ^'^d of a line. The character of 

 the investment is so different from that of ordinary Difflugians 

 that the species may be regarded as pertaining to another genus, 

 for which the name of Catharia would be appropriate. 



Dr. Chapman made the following remarks on the generative 

 apparatus of the Tebennophorus Garolinensis : 



Various have been the interpretations offered from time to time 

 of the generative organs of the Gasteropoda. Thus Cuvier con- 

 sidered what is now regarded as an hermaphroditic organ to be 

 the ovary. Later observers regarded this hermaphroditic organ as 

 the testicle, and considered what is now supposed to be an albu- 

 minous gland the ovary, and which Cuvier regarded as part of 

 the testicle. With reference to these views, I have recently 

 dissected the Tebennophorus Carolinensis, a slug found often in 

 our environs under trees, etc., and found both ova and sperma- 

 tozoa in the organ regarded first as simply the ovary, later as the 



