FISHERY BULLETIN: VOL. 75, NO. 2 



FIGURE 42.—Pleoticus muelleri, 6 37 mm cl, off Buenos Aires Province, Argentina. A, Right spermatophore dissected from terminal 

 ampulla, ventrolateral view. B, Dorsomesial view. C, Left spermatophore dislodged from female, V 59 mm cl, Puerto Madryn, Chubut, 

 Argentina. 



ridge continuous with hump; posterior part 

 narrow, extending as flexible band joining flange. 

 Flange short, with broad mesial base and sinuous 

 lateral margin. Dorsal plate (Figure 42B) large, 

 extending almost from anterior extremity of 

 spermatophore to base of flange, and irregular in 

 contour. 



Compound spermatophore applied to thelycum 

 much as it is in P. robustus. Anterior extremity 

 of geminate body lying opposite female gono- 

 pores, with wings attached to ventral articular 

 membranes of third pereopods. Ventral walls 

 fused mesially while lateral walls diverge dor- 

 sally becoming affixed to sternite XIII, their 

 lateral margins embracing mesial prominences 

 of dorsal articular membranes of fourth pereo- 

 pods. Strong humplike prominences projecting 

 ventrally from sternite XIV, latter serving as 

 place of attachment for broad anterior parts of 

 flaps as well as for intimately fused dorsal plates. 

 From humplike prominences, compound sperma- 

 tophore sloping posterodorsally, and held in 

 position by paired flanges affixed to ventral artic- 

 ular membranes of fifth pereopods. 



The sperm is freed from each sac through an 

 anterior rupture of dorsomesial wall, close to 

 corresponding gonopores. The gelatinous sub- 

 stance which accompanies the sperm within the 

 sperm sac may be observed covering the gono- 

 pores in Figure 41. Spermatophore-bearing fe- 

 males are not infrequent in collections; it seems 

 that the spermatophores in this species as in P. 

 robustus, which are also exceedingly large, 

 become firmly anchored to the thelycum. Accord- 

 ing to Angelescu and Boschi (1960), the spermato- 

 phores in recently caught impregnated females 

 are light green. 



Postembryonic stages. -Boschi and Scelzo (1969a) 

 prepared illustrated keys for the identification of 

 larvae of the three more common Penaeidea in the 

 waters off Argentina. These keys include diag- 

 noses of protozoeae, mysis, and postlarvae of 

 P. muelleri based both on specimens caught in 

 plankton samples and others reared in the lab- 

 oratory. Later, Scelzo and Boschi ( 1975) presented 

 the results of their successful rearing of this 

 shrimp from eggs spawned in the laboratory to 



314 



