352 LOUIS MAX HICKERNELL. 



intestine. Both the esophagus and these glands are obscured 

 by the ventrally lying salivary glands, and it is only when the 

 animal is thoroughly stretched that these structures can be 

 distinguished. 



The stomach-intestine, as seen in the living animal, consists 

 of a yellow, viscous tissue containing granules, fat-droplets and 

 nuclei. By careful observation all of these elements may be 

 recognized. The lumen is usually not seen except in sections. 

 In healthy, active animals the stomach tissue shows its color 

 distinctly. In starved animals the color is lacking in the stomach 

 tissue as Zelinka has pointed out. In newly hatched Philodina 

 the stomach is almost perfectly transparent. 



Just posterior to the stomach-intestine is the "blasendarm" 

 (Fig. i, /;/.) of Zelinka. This is thick-walled but not glandular. 

 It serves for the accumulation of the undigested remains of the 

 food. By the contractions of its walls this material is evacuated 

 from time to time. Darker in color and more homogeneous in 

 structure, this first division of the end gut is the most prominent 

 structure in the posterior part of the trunk of the living Philodina. 



The "blasendarm" leads into the rectum (Fig. I, r), a nar- 

 rower tube in the dorsal wall of which the contractile bladder 

 (Fig. I, c. b.) is found. This bladder is thin-walled, extensible 

 and on either side receives the lateral excretory canals. The 

 bladder pulsates at intervals of fifteen to twenty seconds and in 

 so doing disposes of the accumulated waste which has been 

 emptied into it by the excretory canals. 



Lying on either side of the stomach-intestine are the repro- 

 ductive organs. Since no males of Philodina are known, these 

 organs are always ovaries with their accessory structures. The 

 ovary consists of from six to ten small nuclei which lie close 

 together in a clear syncytial ground substance on the inner 

 margin of the vitellarium. It is not easily seen in living animals 

 unless it contains a developing egg (PI. I., Fig. I, eg.}. 



The vitellarium (Fig. i, v) is especially prominent in living 

 animals. It is a spindle-shaped structure at either end of which 

 is a connective tissue strand which fastens it to the other organs. 

 The anterior strand is fastened to the body wall in the region of 

 the mastax, the posterior one attaches to the digestive system 



