Figure 3. — Penaeopsis sp, USNM 170582, 24.5 mm cl, Bohol Strait, Philippines, Albatross stn 5419. Cephalothorax, lateral view. 5 



mm indicated. 



at right angles to the shaft. The appendices mas- 

 culinae (Figure ID) are considerably less well de- 

 veloped in the present specimens than in juvenile 

 males of P. rectacuta, in which they are circular 

 (Figure IG). and bear only marginal setae. The 

 thelyca of the three specimens differ from those of 

 P. rectacuta in that the lateral borders of the plate 

 of sternite XIV converge strongly (rather than 

 gradually) toward the posterior thoracic ridge and 

 are separated from the ridge by a deep groove, a 

 unique characteristic; the median plate of sternite 

 XIII, although trilobed in one specimen, is cor- 

 diform in the other two, the latter resembling that 

 of P. rectacuta. 



The functional sex of the three specimens can- 

 not be ascertained because their gonads had disin- 

 tegrated. It is unlikely that they were hermaphro- 

 dites for each bears only one pair of gonopores. 

 Because they have a completely developed 

 thelycum one would expect ovipores to occur on 

 the coxae of the third pair of pereopods, but 

 whereas these coxae are similar in outline to those 

 of female P. rectacuta. they lack openings and are 

 covered by a hardened cuticle (Figure 2A-C) like 

 those of males; instead, the coxae ofthe fifth pair of 

 pereopods exhibit a membraneous cuticle with an 

 opening on the proximomesial border. Although 

 the latter aperture is situated on the last pereopod, 

 it occurs on the coxa (Figure 4A) rather than on 

 the bulging articular membrane as it does in typi- 

 cal males (Figure 4B). Furthermore, no terminal 

 ampullae — the ectal muscular region of the vasa 

 deferentia — appear to have been present, even 

 though the skeletal muscles are rather well pre- 

 served. 



Many anomalies of the secondary sexual 

 characters of decapod crustaceans have been re- 



coi'ded, e.g. in lobsters (Chace and Moore 1959, 

 among others) and crayfishes (Turner 1924, 1929, 

 1935). Recently Zongker (1961) described many 

 sexually aberrant individuals within a population 

 o{ Caniharus niontanus acuminatus Faxon 1884. 

 Among the aberrant individuals she found were 

 females (sex identified by examination of the 

 gonads) lacking ovipores on the coxae ofthe third 

 pair of pereopods, but with "male openings" on 

 those ofthe fifth, an anomaly similar to that exhi- 

 bited by my specimens. In these shrimp, the aper- 

 tures are not typical of penaeoid males because of 

 their location on the coxae rather than on the 

 articular membranes. Being present on the coxae, 

 they resemble female openings; however, ovipores 

 are typically subcircular rather than slitlike and, 

 furthermore, they are characteristically situated 

 on the mesial surface of the coxa, dorsal to the 

 coxal plate, instead of on the ventral face as in my 

 specimens. 



Individuals ofthe superfamily Penaeoidea bear- 

 ing both a thelycum and a petasma have not been 

 recorded previously in the literature. Based on size 

 distribution and characters ofthe endopod ofthe 

 first pair of pleopods in females, Heegaard ( 1967, 

 1971, 1972) suggested the possibility that protan- 

 drous hermaphroditism occurs in Solenocera 

 memhranacea (Risso 1816) and also in Perjaeu.'i 

 kerathurus (Forskal 1977), but no individuals 

 with both petasma and thelycum were found by 

 him. The external genitalia in my three specimens 

 causes one to suspect that they might be transi- 

 tional forms and that therefore at least some 

 members ofthe genus Penaeopsis exhibit protan- 

 drous hermaphroditism (protandrous because at 

 their size the thelyca are fully developed whereas 

 the petasmata are relatively small). Their rather 



689 



