OLTGOTREMA PSAMMITES. 259 



probability to the genus Platyscelus, the members of which 

 are free living. Therefore the contents of the stomach go 

 to prove that Oligotrema is able to capture and swallow 

 relatively large and active Crustacea^ a feat which its six 

 muscular arms are well adapted to perform. 



The intestine is a narrow tube which takes its origin 

 from the left side of the anterior and dorsal angle of the 

 distal limb of the stomach. It passes at once into the ecto- 

 plerome of the left side and runs backward, on the inner side 

 of the ovary, towards the dorsal surface. On reaching the 

 dorsal surface jusfc in front of the posterior limit of the 

 stomach it turns forward, and, still enclosed in a thickening 

 of the ectoplerome, it is continued forward to the atrial 

 siphon, and opens by a minute anal orifice in close proximity 

 to it. The intestine of my specimen is empty. In the first 

 part of its course it is lined by a glandular epithelium com- 

 posed of small cells liaviug the character, as far as their state 

 of preservation allowed me to determine it, of somewhat squat 

 goblet-cells. In the last section of the intestine the glan- 

 dular cells give place to a columnar epithelium which appears 

 to have an excretory function, as the free ends of its com- 

 ponent cells are loaded with highly refracting nodules of a 

 brownish-yellow colour (fig. 31), and a number of similar 

 concretions are contained in the lumen. The blood-spaces 

 surrounding this terminal section of the intestine are full of 

 corpuscles of various kinds, whose accumulation in this region 

 may be held to afford additional evidence of the excretory 

 nature of the epithelium. 



The Reproductive Organs. 



Oligotrema, like other Ascidians, is moncocious. The 

 ovaries are paired, and open into the atrial cavity near and 

 somewhat in front of the anus, by right and left oviducts. 

 The ovaries, as shown in figs. 3, 34, 13, 14, have the form of 

 a pair of sinuous bands embedded in the ectoplerome of either 

 side of the body at about the level of the atrial siphon. They 



