No. 2.] AJVATOA/y OF A SPECIES OF FLATYASPIS. 63 



The nervous system was only imperfectly seen. I did not 

 recognize it at all in the living animals, and it barely shows in 

 the total preparations, but in transverse sections it is clear that 

 there is a large band of fibers crossing the pharynx dorsally — far 

 forward (in section No. 10), and extending down ventrally around 

 the pharynx so as to more than half encircle it. A lateral nerve 

 can be traced posteriorly in a few sections. It shows at Nv. 

 in Fig. 4. 



Just posterior to this nerve band there are located two sym- 

 metrically disposed organs. They are shown at Oc, in Figs, i 

 and 4, where their location is indicated. They are, apparently, 

 invariable structures, very noticeable in living animals, and I 

 have found them in every individual that I have examined 

 without any exception. They are spherical bodies located in 

 the parenchyma, deeply below the surface and near the ante- 

 rior boundary of the pharynx ; they are posterior and close to 

 the cerebral nerve mass. They are spherical and apparently 

 hollow. The surface is pigmented ; the pigment, in the form 

 of minute grains, is clearly visible under the immersion lens ; 

 these grains are, apparently, scattered on all parts of the sur- 

 face of the sphere, but they are much more closely deposited 

 on the inner and upper side. I have not thus far recognized 

 any lens. I have from the first considered them eyes ; their 

 invariable presence, their position in the neighborhood of the 

 cerebral nerve mass, and the presence of pigment demanding 

 this identification. If, however, we accept them as eyes, we 

 must recognize that P. anodontae differs in possessing them 

 from adult trematodes generally. It is well known that eyes 

 are present in early stages of the trematodes, but they are not 

 hitherto recorded of adults, so far as I am able to learn. The 

 accounts of P. lenoiri do not mention this point, and the 

 illustrations do not shed any light on the question ; so far as 

 can be ascertained from them, these organs are wanting in the 

 African form. There is no room for doubt as to the Chautau- 

 qua animals being adult; the condition of the reproductive sys- 

 tem at large and the presence of eggs and embryos settle that. 

 It is, perhaps, hardly worth while to speculate on the matter 

 now, but I cannot help noting the possible correlation between 



