MOLGULA MANHATTENSIS. 195 



2. The endostyle is a ciliated groove along the mid-ventral 

 wall of the pharynx. In a very fresh specimen, cut out a large 

 piece of the ventral and left lateral wall of the pharynx, prefer- 

 ably near the siphon, mount it inside up in sea-water and ex- 

 amine with a microscope. Note the structure of the endostyle. 

 At some distance from the endostyle, on each side of it, note the 

 meshwork of bood-vessels, and the curved openings or stig- 

 mata lined with cilia. Of what use are the cilia? 



3. Anteriorly the endostyle is continuous with the peri- 

 pharyngeal ciliated bands, which encircle the oral end of the 

 pharynx. From the point where they unite dorsally the dorsal 

 lamina extends backward along the mid-dorsal line of the phar- 

 ynx. At its posterior end will be seen the small opening into 

 the esophagus. 



Do you understand how the animal captures its food and 

 how the endostyle, peri-pharyngeal bands, and dorsal lamina are 

 used? 



4. In front of the anterior end of the dorsal lamina note the 

 small, volute-shaped dorsal tubercle. This is the extremity of 

 the hypophysis, a tube connecting the subneural gland with the 

 oral cavity. 



5. A ring of oral tentacles will be seen in the mouth, anterior 

 to the peri-pharyngeal bands. Of what use are tentacles in 

 the mouth? How many tentacles are there? 



6. The very short esophagus opens into the stomach, which 

 will be recognized by the brown digestive glands that cover 

 it. From the stomach the intestine forms a loop on the left 

 side, and is easily traced to the anus, which opens dorsal to the 

 pharynx in the atrial chamber. A longitudinal fold, the typh- 

 losole, extends throughout the intestine. What is the use of 

 such a fold ? 



Reproductive System. On each side of the body, adherent to 

 the inside of the mantle, is an elongate hermaphrodite gland. 

 Each gland consists of a lighter part, the testis, and a darker part, 

 the ovary. The gonoducts open on the outer wall of the atrial 

 cavity near the base of the atrial siphon. Each consists of two 



