Stomatopoda in the Bernice P. Bishop Museum 



By Charles Howard Edmondson 



INTRODUCTION 



The Stomatopoda which represent one of the higher orders of 

 mahicostracous Crustacea constitute a clearly defined group and 

 may he recognized hy the following characteristics. 



The carapace is relatively small and only partly covers the 

 cephalothorax, leaving" at least the four posterior thoracic seg'ments 

 exposed. The rostrum is separated from the carapace by a dis- 

 tinct suture. The alxlomen is well developed. The eyes are 

 stalked and carried on distinct moval)le segments, as are also the 

 first pair of antennae. The second pair of thoracic appendages 

 are developed into raptorial limbs in which the terminal segment, 

 called the dactylus, closes upon the preceding one, the manus, 

 like a knife blade. IVxsterior to the raptorial limbs are three pairs 

 of tlioracic a]:)pendag"es constructed on the same general plan as 

 the former but very much smaller. The three posterior thoracic 

 segments bear jjiramtms walking legs. Of the seven abdominal 

 segments each of the first five bears a pair of appendages, the 

 swimmerets, to which are attached tufted gills. The sixth segment 

 also bears a pair of appendages, the uropods, which, with the 

 seventh segment, the telson, serve as a tail fin. 



All recent Stomatopoda are included in a single family, 

 Squillidae. the characteristics of which are the same as those of 

 the order. 



In this group relationship between the several genera and also 

 between species is based largely upon the peculiar features of the 

 sixth and seventh abdominal segments, the raptorial limbs, the 

 eves, and the rostrum. 



llrooks,^ in tracing the generic relationship between the species, 

 calls attention to the important significance of the accessory organ 

 of the first abdominal appendage of the male stomatopod. 



'Brooks. W. K., Report on tlie Stomatopoda : Voy. H.M.S. "Challen- 

 ger," Zoology, vol. i6, p. 13, 1886. 



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