1913-] S. Kemp : Crustacea Stomatopoda of the Indo-Pacific Region. 15 



SYSTEMATIC PART. 

 STOMATOPODA. 



The Stomatopoda belong to the sub-class Malacostraca and constitute the only 

 order of the last of the four divisions into which the second series of the sub-class is 

 divided. This division is known by the name Hoplocarida, and is defined by Caiman 

 (1909) in the following terms : — 



" Carapace leaving at least four of the thoracic somites distinct; two movable 

 segments are separated from the anterior part of the head, bearing respectively the 

 pedunculate eyes and the antennules ; protopodite of antenna of two segments ; 

 mandible without lacinia mobilis ; posterior thoracic limbs with protopodite of three 

 segments (the relation of the segments of the anterior thoracic limbs to those of the 

 limbs in the other divisions is doubtful) ; an appendix interna on pleopods; hepatic 

 caeca much ramified ; heart much elongated, extending through thoracic and abdomi- 

 nal regions ; spermatozoa spherical ; development with metamorphosis, a free-swim- 

 ming nauplius stage is not certainly known." 



Since the time when it was discovered that the forms classed as Erichthidae 

 were nothing more than larval stages, the order Stomatopoda has been held to com- 

 prise only a single family, the Squillidae. It seems, however, that the species 

 belonging to the fossil genus Sculda, Münster, are distinguished from the recent 

 forms by features sufficiently important to entitle them to separate family rank and 

 it may be expected that, with the acquisition of more perfect specimens, other 

 characteristic differences will be disclosed. In the present state of our knowledge the 

 families may be separated from one another as follows : — 



I. Exopodite of uropod composed of a single segment . . . . Sculdidae 



(fossil). 

 II. Exopodite of uropod composed of two quite distinct segments . . Souillidae 



(fossil and recent). 



In the Sculdidae the spines on the margin of the telson appear to have all been 

 movable and in this respect differ from those of recent Stomatopoda, while from the 

 figures which Kunth gives (1870) it seems that only three thoracic segments are 

 left uncovered by the carapace. The form of the raptorial claw is unfortunately 

 unknown, 1 but that the limb is far less conspicuous than in the Squillidae may be 

 surmised from the fact that, though no trace of it can be discovered in Sculda, it has 

 been found in the much scarcer fossil Squilla.' 1 



1 Kunth (1870) is of the opinion that the raptorial claw is traceable in one of his specimens of 

 Sculda pennata in which the under surface is shown, but in his figure (pi. xvii, fig. 2) this is far from 

 obvious; it seems more probable that the part referred to is merely a portion of the reflexed lateral 

 margin of the carapace. 



% Squilla lewisi, Woodward, Q. J. Geol. Soc, xxxv, 1879, pi. xxvi, fig. 4. 



