12 



The mature male has a spermatophore always in the dilated end of 

 the ductus ejaculatorius of each side and the mature female carries 

 always a pair of spermatophores in the seminal receptacle, even soon 

 after the spawning. 



The color of the animal is light brown or greyish brown with 

 about eleven transverse bands of darker color. The color of the 

 rhipidura is splendid, it is fringed with red hairs and its margin is 

 colored with blue and yellow in succession. Appendages are greenish. 

 Immature specimens are darker and bluish in color (PI. I, 1). 



The male reaches maturity when it is 12 cm. in length, while the 

 female matures at 15 cm. The largest specimen examined is 27 cm. 

 in length. 



This animal prefers the sandy bottom. When young it is found 

 in a very shallow water ; but after it has grown old, it seeks deeper 

 water, especially in colder months. 



Chiefly captured with trawls. 



This is generally known under the name of " kurumayebi." 



PENAEUS LATISULCATUS. Nov. s P ec. 



(pi. n, 2) 



The shell smooth, polished, thick and hard. The rostrum slightly 

 curved, is armed with io, sometimes 11 teeth on the upper and 1 

 tooth on the lower side of it. It is not longer than the peduncle of 

 the first pair of antennae. Three grooves at the middle part of the 

 carapace almost reach the posterior margin of it, as is the case with 

 P. canaliculatiis ; but the lateral grooves are broader than the median 

 groove as in P. caramote. In immature specimens, however, the three 

 grooves are almost equal to each other in breadth. The flagellae of 

 the first pair of antennae are very short. A short styliform spine is 



