2 PROCEEDINGS OF THE NATIONAL MUSEUM. vol.55. 



novae, Alces alces, Ovis mexicana, and Odocoileus americanus. Con- 

 trary to the statement commonly made in descriptions of this species 

 placing the limits of the number of lateral uterine branches between 

 6 and 8, as many as 10, and even more, may be found 



TAXONOMY AND MORPHOLOGY. 



Phylum PLATYHELMINTHES. 



Phylmn diagnosis. — ^Worms which are flattened dorso-ventrally 

 and are bilaterally symmetrical. No body cavity present. Digestive 

 cavity present or absent; when present, incomplete — that is, with an 

 initial mouth aperture but without a terminal anal aperture, except 

 in the Nemertinea. Organs and systems of body embedded in a 

 parenchyniatous tissue. Muscular systems well developed. Nervous 

 system consisting of an anterior nerve ring, surrounding the eso- 

 phagus when the latter is present, and of longitudinal nerves, with 

 ganglia, passing caudad and sending oif branches. Skeletal system not 

 represented, although calcareous corpuscles are commonly present in 

 the body parenchyma of the Cestoda. These probably have little or 

 no skeletal function. Circulatory system not represented. Respira- 

 tion cutaneous. Excretory system consists of two or more longitudi- 

 nal or coiled tubes, with terminal openings to the exterior and ulti- 

 mate origins in nephridial flame-cells. Reproduction sexual or asex- 

 ual, and development direct or with alternation of generations. 



Class CESTODA. 



Class diagnosis. — Platyhelminthes : Worms with external segmen- 

 tation, exceptionally without, and with internal anatomy showing 

 segmental arrangement and commonly arranged with reference to 

 the external segmentation. At one end is a structure called the head, 

 but variously regarded by writers as actually an anterior cephalic 

 structure, or as a posterior pedal structure. This is essentially an 

 organ of attachment and is provided with two suctorial grooves or 

 bothridia, or with four more or less cuplike depressions or suck- 

 ers. There may also be one to numerous crowns of hooks on a 

 muscular apex or rostellum in forms with four suckers, and also on 

 the suckers themselves in these forms. The body segments are small- 

 est near the head. No digestive system present; food absorbed by 

 osmosis through the body surface. Body parenchyma usually con- 

 tains numerous calcareous corpuscles scattered through it. Nervous 

 system consists of a nerve ring located in the head and sending two 

 main nerve systems back on each side of the body or strobila, and of 

 the nerves extending from the ring and the lateral nerve trunks and 



