THE GEPHYREA OF JAPAN. 23 



posteriorly to the roots of the dorsal retractor muscles ; about 

 the anterior half of the organ is connected with the body-wall 

 by a mesentery. 



A large number of specimens from Enoura in the Province 

 of Suruga, referable to this species, are preserved in the Zoological 

 Museum of the Science College, Imperial University of Tokyo. 

 I myself have obtained three specimens from a shallow bottom 

 (5 hiro deep) near the Misaki Marine Laboratory. According 

 to Selenka, Hilgendoef collected the species at Enoura and 

 also at Hakodate. It seems highly probable that this species 

 will be found in more southern localities than Enoura, for the 

 fauna of Enoura, as is admitted by all Japanese zoologists, 

 comprises many subtropical forms. 



In dissecting specimens of the present species, it almost 

 always happened that a moderately large globular body was 

 found attached to the dorsal side of the œsophagus nearly 

 always in the same position. I have ascertained by a study of 

 sections that the said body is a sac w^hich contains a number 

 of small parasitic worms ; the parasites are imbedded in a 

 dense mass of leucocyte-like cells. Each parasitic worm is 

 externally enveloped by a rather thick cuticula of a bright yellow 

 color ; it is provided with a large and a small sucker, both situated 

 on the flattened side of the body. Spengel described quite similar 

 worms in the general body-cavity of Balanoglossus kapferi ; he 

 thought them to be the young of a Distoma species. As to 

 the body-form, the structure and position of the two suckers, 

 etc., I see no noticeable difference of importance between the 

 parasites described by Spengel and those found by me in Phymo- 

 soma japonicum. 



