A. E. Verrill — 3farine Planarians of JVew Midland. 461 



side, and also a median anterior branch ; the branches sub- 

 divide arborescently and usually anastomose distally. Ovarian 

 organs all similar ; no distinct vitellaria. Male and female 

 openings generally separate. Marine. 

 II. MoNOGONOPORA or Tricladidea. In these the central stomach 

 is small and divides at once into three parts, viz : a median 

 anterior, and a pair of posterior branches, from all of which 

 simple or divided lateral branches go forth. Germai'ia distinct 

 from the vitellaria. Terrestrial, fluviatile, and marine. 



DIGONOPORA Stimpsou; POLYCLADIDEA Lang. 



Digonopora Stimp., Prodromvis, p. 1, in Proc. Acad. Nat. Sciences Pliilad., ix, p. 

 19, 1857. 



Body generally rather large, broad, flat, often foliaceous with 

 thin undulating margins. Very changeable in form, mouth situated 

 on the lower side, often near the center, sometimes far forward. 

 Pharynx sometimes long, tubular ; often broad, many lobed or pli- 

 cated ; digestive organ has a distinct, wide central portion or 

 stomach, from which arise more or less numerous, large lateral 

 branches which usually fork at first, or subdivide in a dendritic man- 

 ner, but in most cases anastomose distally and form a reticulated 

 netwoi'k ; anterior branch of the stomach situated medially, passing 

 above the cerebral ganglion, which is bilobed. 



Ocelli usually small and numei"ous, variously arranged, some are 

 generally grouped over the cerebral ganglions. Tentacles sometimes 

 present, with or without ocelli ; often absent. 



Reproductive organs hermaphrodite. Ovaries and testes numer- 

 ous, scattered ; the ovigenous and vitelligenous organs not separate. 

 External genital openings generally two, situated behind the mouth, 

 the female behind the male ; sometimes there are two female open- 

 ings, one behind the other ; rarely there are several male organs, each 

 with a separate opening. The species are all marine. 



Tribe, Aootylea Lang. 



Acetabulum wanting. Pharynx short and wide ; mouth in the 

 middle of the body, or a little forward of, or behind the middle. 

 Branches of the stomach ramose or reticulated. Copulatory organs 

 situated in the postei-ior part ol the body. Tentacles, when present, 

 two dorsal, usually having ocelli ; often wanting. 



