FISHERY BULLETIN: VOL. 71, NO. 1 



Table 3. — Comparison of porcellanid larvae on the basis of distal armature of telson 



processes and telson form.^ 



1 A = Lebour's (1943) definition of Porcellana telson. Telson about IV2 times as wide as long with seventh 

 pair of processes situated outside and below central prominence in stage I. In stage II, an eighth 

 pair of processes is added on the central prominence. 



B = Leb>our's (1943) definition of Petrolisthes telson. Tefson about as long as wide with seventh pair of 

 processes stiuated on central prominence in stage I. In stage II, a single median spine (or setae) added 



C = Fits neither A nor B exactly. 



onyx, Porcellana, and Pisidia. A third telson 

 type (C, Table 3) has since been described and 

 to date includes only the larvae of Petrocheles 

 spinosus from New Zealand. 



Among larvae possessing a similar telson 

 form, further systematic separation following 

 generic lines appears to be possible on the basis 

 of the position of the long telson setae (processes 

 3 through 7) armed distally with conspicuous 

 spines. This is particularly true of 13 larvae of 



known adult origin possessing the Petrolisthes 

 type telson. Of these 13 species, only the larvae 

 attributed to Pachycheles natalensis differ from 

 other larvae of the same genus. 



The known larvae possessing the Porcellana 

 type telson are more difficult to group using tel- 

 son seta armature alone. Only larvae of the 

 single known species of Euceramus can be dis- 

 tinguished from other known larvae of this 

 telson type on the basis of setal armature. In 



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