166 s. GOTO. 



posterior ventral border. A biuidle, which soon divides itself into 

 two smaller bundles, proceeds from the ventral side, and is attached, 

 one of the branches to the same point as the posterior dorsal bundle, 

 the other branch a little more ventrally and anteriorly. Two weaker 

 bundles start, in addition to the above, from the upper and lower lips 

 of the mouth, and are attached to the corresponding borders of the 

 sucker. I have observed some of the fibres of these various bimdles 

 directly continued through the substance of the wall, and inserted on 

 the cuticula that lines the cavity of the sucker. By the combined 

 action of these muscles, the worm can exercise a strong suction on the 

 gill of the host, and. extract its blood. 



Besides these suckers, there is a pair of glands at the entrance of 

 the mouth, just anterior to the suckers, which seem to be pecnHar to 

 Dipl. nipponicum. They can be seen well in a living specimen under 

 the cover glass, or in preparations of the entire worm, as a round, 

 paired body. One of them is seen in section in Fig. 8, which shews 

 it to be a gland formed bv the invagination and local modiiicarion of 

 the epidermis. It has generally a reniform cavity, which opens into 

 the mouth by a canal, just anteriorly and close to where the sucker 

 opens into the mouth. The epidermis is continued into the canal for 

 a certain distance, and then changes its character, becoming firmer 

 and refractive like the cuticula. The cavity of the gland is destitute 

 of any distinct epithelium, but is generally filled with a granular mass, 

 which stains very well. This mass is densest near the wall, and gra- 

 dunlly becomes thinner towards the centre, where there is generally 

 an empty space. I have often observed the exit canal filled with 

 a deeply stained granular mass, very similar in appearance to the con- 

 tents of the sticky glands of DacNilogi/riis and other allied forms, and 

 which is doubtless the sticky secretion of the gland. Next the gran- 

 ular content is a basement membrane. The wall is exceedingly 



