68 PROCEEDINGS OF THE NATIONAL MUSEUM vol. loe 



Whole mount features: The body appears of elongated oval form 

 with rounded ends (fig. l,a) but both specimens were distorted by 

 fixation. The larger specimen is 20 mm. long by 8 mm. wide. The 

 color is indeterminable, apparently a light brown with fleckings of 

 darker brown. Around the anterior margin is a narrow band of 

 small eyes, about two eyes deep. Well back from the anterior margin 

 are found the remaining eyes, in the form of tentacular and cerebral 

 clusters. An enlarged view of these eyes is given in figure 2,a, 

 drawn with the aid of a camera lucida. The narrow elongate pharynx 

 occupies the central part of the body and to either side of it are seen 

 the coiled uteri stuffed with eggs. Immediately behind the rear end 

 of the pharynx is located the massive penis, and behind this the 

 irregular Lang's vesicle may be dimly seen. 



CopuLATORY apparatus: As the taxonomy of polyclads is based 

 on the details of the copulatory apparatus, it becomes necessary to 

 examine this apparatus in sagittal serial sections. The copulatory 

 region of both specimens was removed and sectioned, but neither 

 series of sections was entirely satisfactory as the ventral wall was 

 found injured in both cases. The sagittal view in figure 1,6 was 

 constructed with the aid of both series of sections. 



The penis depends from the roof of the male antrum as a massive 

 irregular body of somewhat oval shape, and is housed in a male 

 antrum that also is shaped very irregularly. The penis appears 

 centrally depressed with a thickened periphery. This central part 

 is devoid of the small prostatic apparatuses characteristic of the 

 family. The sperm ducts approach the anterior end of the penis 

 dorsally and unite to a common sperm duct that shows a small en- 

 largement containing sperm. From this enlargement the ejaculatory 

 duct descends and opens into the anterior part of the male antrum 

 without the formation of any definite penis papilla. A prostatic 

 vesicle is also absent. The thickened periphery of the penis is beset 

 with numerous small prostatic apparatuses that appear in median 

 sagittal section only at the two ends of the penis and are best repre- 

 sented in parasagittal section as in figure 2,c. They are all alike 

 morphologically and of about the same size, although some anterior 

 ones are slightly larger. Their histology has been repeatedly illus- 

 trated and hence need not be given here. In this species, prostatic 

 apparatuses are absent from the antral wall. The penis is fairly 

 muscular with fibers in various directions. Behind the penis there is 

 present a muscular pocket of the male antrum devoid of prostatic 

 apparatuses. The male antrum opens near its posterior end by a 

 rather wide gonopore. 



Shortly behind the male gonopore, the female gonopore opens 

 narrowly. From it the vagina ascends with a decided posterior slant 



