644 



BULLETIN 100, UNITED STATES NATIONAL MUSEUM. 



Fig. 3. 



-Arrangement of etespots in Pseudoceros 

 rdbrotentacolatus. 



buff bands of almost similar breadth, each of which was bordered by 

 a narrow, deep, tawny-brown stripe. One followed the median line ; 

 the other two ran parallel to it, with an interspace as broad as 



or broader than the buff 

 bands. The ventral sur- 

 face was of a uniform pale 

 buff color with a bright 

 cobalt marginal stripe, 

 just as the dorsal. 



Numerous small eye- 

 spots are found irregu- 

 larly arranged along the 

 margin of the tentacular folds and also occur forming a crowded 

 cluster over the brain. 



The mouth is placed at the beginning of the middle third of the 

 body and opens nearly into the middle of the much-folded pharynx, 

 which is nearly one-third as long as the body. The main gut is 

 narrow, of a considerable length, and gives rise to numerous pairs 

 of lateral branches, the subdivisions of which do not undergo anas- 

 tomosis. At the hind end the 

 main trunk becomes somewhat 

 dilated. The ventral sucker 

 occurs a little anterior to the 

 hind end of the middle third of 

 the body. 



The male gonopore lies in the 

 median line slightly behind the 

 pharyngeal cavity. The vas 

 deferens pursues a backward 

 course and bends inward a lit- 

 tle behind the genital opening, 

 finally to unite with its mate of 

 the opposite side into a median 

 canal, which rises upward to 

 continue with the anteriorly di- 

 rected, wide seminal vesicle hav- 

 ing a thick muscular coating 

 composed of two sets of fibers, 

 circular and longitudinal. An- 

 teriorly the vesicle gives rise 



to a slender duct, the ejaculatory duct, which turns abruptly down- 

 ward just behind the prostate, and after receiving the duct of this 

 organ enters the penis. The prostate is of a pyriform shape and 

 lies just dorsal to the base of the penis, which is represented by a 

 long chitinous stylet hanging vertically in the sheath. The antrum 



am 7:5 £ 



Fig. 4. — Male genital organs of P. rubro- 

 tentacdlatus in sagittal section. am, 

 antrom mdscolinum ; sv, seminal tbs- 

 icle. Other letters as in Fig 2. 



