24 



Penacus curvirostris, Stimpson, Proc. Ac. Nat. Sc. Philadelph. 

 p. 113 (i860); Ortmann, Zool. Jahrbuch. Abth. Syst. p. 45 i (1890). 

 ? Penaeus barbatus, de Haan, Fauna Japon. Crust (1849). 

 ? Penaeus granulatus, Haswell, Proc. Lin. Soc. N. S. Wales iv 



(i879). 



Penaeus anchor alis, Sp. Bate, Challenger Rep. Crust. Macrura (1888). 



The whole surface of the shell is covered with setae. The rostrum 

 is straight and short in males ; but in females it is a little elevated at 

 the apex and is subequal in length to the peduncle of the first anten- 

 nae. Generally 8 dentate. Continuous to the rostrum there is a faint 

 kiel on the carapace. The antero-inferior corner of the carapace is 

 more or less pointed ; but it does not form a tooth. The second joint 

 of the first two pairs of pereipoda spined. The pleon is kieled from 

 the second somite backward. The tail segment is grooved and is 

 armed on each margin with three small spines. 



The central plate of the thelycum is lozenge-shaped and concave. 

 The lateral plates are short and small, united at the median line (PI. 

 VII, 10 A). The seminal receptacle consists of two membranaceous 

 sees (PI. VII, 10 B), having narrow slits for the opening. After copula- 

 tion the central plate is covered with an amorphous gum-like substance 

 (PI. VII, 10 C). 



The petasma is T shaped (PL VII, 10). The vas deferens is 

 slender and has several coils. The ductus ejaculatorius becomes 

 gradually thick towards the genital opening. Smermatozoa are top- 

 shaped. Some fifty or more spermatozoa are grouped in an ellipsoidal 

 sac or spermatophore. In this species a great many such sacs or 

 spermatophores are transferred to females by copulation. Males have 

 ripe spermatozoa whole round a year. 



The color is light brown or greyish brown. 



The female specimen attains the length of 12.5 cm., the male 10.5 

 cm. The female reaches maturity when it is 7.5 cm. in length and the 



