•14 



PENAEUS ASHIAKA. Nov. Spec. 



(PI. Ill) 



The shell is rather thick and smooth. The rostrum slightly curved, 

 7 dentate above and 3 dentate below. The dorsal median carina of 

 the carapace is canaliculated and extends almost to the posterior 

 margin of the carapace. The lateral grooves do not extend to the 

 posterior margin of the carapace, but terminate abruptly at its middle 

 part, a little behind the gastric tooth. The first pair of pereiopoda is 

 armed with two spines (one on basis, the other on ischium) and the 

 second pair with one spine on basis. The telson has no armature. 



The seminal receptacle (PI, VII, 3 A, 3 B) resembles that of P. 

 latisulcatus, but the calcified appendage to the median plate of the 

 thelycum is wanting. 



The petasma (PI. VII, 3) is longitudinally folded. Its outer part 

 is thick, calcified and is furnished with very minute teeth at the anterior 

 margin. The distal end of the inner lamina short. 



The spermatophore has a long, soft, band-shaped appendage which 

 is united to the spermatophore nearly with a right angle to its axis. 



The color is greyish brown or bluish and about twelve pairs of 

 darker and lighter shades alternate each other. The appendages are 

 carmine red. The second antennae are colored with red and light 

 brown in alternation. 



The animal attains the length of 22 cm. The largest male exa- 

 mined is 18.5 cm. in length. 



Roughly speaking this species is found along the southern half of 

 our coast. 



Is known under the names of "ashiaka," "kuroyebi," "kumayebi," 

 etc. 



