SCOTTO LARVAL DEVELOPMENT (IF CUBAN STONE CRAB 



Table 3. — Taxonomically important zoeal characters in two species of Menippe. Data on M . mercenaria taken from Porter (1960). 



cenaria. His data show that difference.s between 

 megalopae of the two species are exhibited chiefly 

 in the spination of the pereiopods. Menippe mer- 

 cenaria has 5 or 6, 2 or 3, and 1 small spine on the 

 ischia of walking legs, one, two, and three, respec- 

 tively; and 2 small spines on the proximal inner 

 edge of the merus of the first walking leg. Menippe 

 nodifrons exhibits variable setation on these same 

 segments but lacks spines. Kurata also stated that 

 the ischium of the third maxilliped of M. mer- 

 cenana has 9 small spines; in M . nodifrons vari- 

 able setation occurs, but 25 setae are usually 

 found. 



Among other species of Menippe only the first 

 zoeal stage of the Indo-Pacific M. /•;/ mph ii has been 

 described (Prasad and Tampi 1957). As indicated 

 in Table 2, the three congeners have a similar first 

 stage, but differ in antennular aesthetasc number, 

 .setation of the maxillary coxal endite. setation of 

 the basi- and endopodite of the first maxilliped. 

 and endopodite setation of the second maxilliped. 

 As noted in the introduction, there is some ques- 

 tion as to whetherM. rumphii is synonymous with 

 M . nodifrons. The complete larval development of 

 M . rumphii is needed to establish the status of this 



species and its taxonomic relationship to M . nodi- 

 frons. 



Distinguishing Morphology of 

 Xanthidae Larvae 



According to Lebour ( 1928), larvae of the family 

 Xanthidae exhibit the following characters: 



1. One prezoeal and four zoeal stages. 



2. Carapace with dorsal, rostral, and one pair of 

 smaller lateral spines. 



3. Antenna with rudimentary exopodite, or 

 with one nearly as long as the spinous pro- 

 topodal process. 



4. Abdomen with lateral knobs on somites 2 

 and 3, somites 3-5 or 6 with lateral spines in 

 all stages. 



5. Telson furcae with 3 lateral spines or with 1 

 tending to disappear in later stages. 



Wear 1 1970) reviewed the diagnostic characters 

 of certain xanthid larvae and enumerated sev- 

 eral conclusions about Menippe. Known larvae of 

 the genus Menippe. reared under laboratory con- 



379 



