Edible Medusae. 207 



appendage are very numerous, and generally the long fusiform ap- 

 pendage is found to be bigger and longer towards the distal end of 

 the lower portion of the arm. Some of them attain the length of 

 300 mm or more in a füll grown specimen. They fall off easily. There 

 is no special terminal appendage which may be distinguished easily 

 from the others by the superiority of its size. 



The lower portion of the arm is about twice as long as the free 

 part of the upper portion, but is shorter than the long fusiform append- 

 ages. The upper portion is about as long as the scapulet. 



The gastrovascular System is very complex. The canal-system 

 of the subumbrella is nearly alike to that of Bhizostoma his^ndium 

 Vanhoeffen ^). The circular canal is indistinct in mature specimens ; 

 but its original position is indicated by the swollen, middle part of 

 the adradial canal (Fig. 2). Inside of the circular canal, the perradial 

 and interradial canals anastomose with the canal arcade; but the 

 adradial canals do not. From the lower border of the gastric cavity 

 originate four perradial canals, which correspond to the crucial canal 

 of the Cranibessidae , and there also originate the canals for the 

 scapulets (Fig. 1). Fach limb of the crucial canal is divided into 

 two, so that there are eight canals for the eight oral arms. Fach 

 arm canal (Fig. 4) gives off many branches, the largest of which is 

 branched from the middle part of the canal where it is divided into 

 two horizontal branches. The largest branch-canal runs through the 

 longitudinal axis of the lower portion of the arm and gives off a few 

 lateral branchlets; but it is divided into many short branchlets at 

 the distal end. These branchlets are almost equal in size and there 

 is not a specially larger one for the terminal appendage, as it is usu- 

 ally the case with the medusae of the genus Rhisostotna (Pilema of 

 Haeckel). Each of the two horizontal branches gives oö' four or 

 five branchlets. The largest branchlet is situated nearest to the 

 longitudinal axis of the lower portion of the arm. These branchlets 

 are ramified again and again and open in suctorial frills of the dorsal, 

 or abaxial, wing of the lower part of the arm. 



The color is generally blue, but sometimes it is dark red. The 

 sucking frills are brown, while the appendages are milky white or 

 colorless and nearly transparent. The genital gland is yellow. The male 

 genital gland is lighter in color than that of the female. 



1) Vanhoeffen, Untersuchungen über semäostome und rhizostome 

 Medusen, 1888, p. 32, tab. 5, fig. 1, 2. 



