20 



and is provided with a pointed cap at the apex. The spine is longer 

 than the second joint of the same pereiopoda. Males have moreover 

 a tooth on the fourth joint of the fifth pereiopoda. The fourth joint of 

 the fourth pereiopoda is broad and forms a tooth-like projection. 

 In the pleon there is a dorsal median kiel. It is rather faint in the 

 first to the third segments. The pleuron of the first somite has an 

 incision which is more marked in males than in females. The peduncle 

 of the pleopoda nearly naked, leaving a narrow setae-grown groove. 

 In males the sixth pleopoda has a tubercle on its peduncle. 



The central and the lateral plates of the thelycum (PI. VII, 7 A, 7B) 

 are almost equal in length. The larger part of the central plate is 

 vertical, but it is horizontally expanded at the posterior end. Lateral 

 plates are convex and their inner margin runs along the entire length 

 of the central plate. Hence the ostia to the seminal receptacle are 

 wide and conspicuous. Females receive by copulation a pair of milky 

 white, leaf-shaped bodies on the thelycum (PI. VII, 7 C). These peculiar 

 bodies have no direct connection with the spermatozoa, but are at- 

 tached to the posterior, broad portion of the central plate by means 

 of a glutinous substance. This species does not form spermatophores, 

 but the spermatozoa in the seminal receptacle form a nearly solid 

 mass. 



The petasma (PI. VII, 7) is complicated. The anterior end of its 

 inner lamina long and bent backward. 



The vas deferens long and coiled several times. The ductus 

 ejaculatorius is thick walled and its end, next to the external opening 

 is swollen and is divided into three partially separated chambers. 



The color of the animal is pale yellow with numerous small green- 

 ish spots. The external margin of the rhipidura greenish. 



The animal generally reaches the size of 13 cm. The largest 

 male I examined was 14 cm, the largest female 15 cm. 



The animal copulates from the beginning of June to the end of 



