424 



CRUSTACEA. 



perate zones. AltLoiigli \vc have observed a very great uumber of individuals, wc have never 

 met with one carrying eggs. Their habits are entirely unknown. It is, howeverj beyond a 

 doubt, that those species with powerful claws use them for the purpose of seizing their prey 

 in the- same nnniiier as those Ortho})tura whicli are named Mantes*; and it is on ueenunt of 

 this conformity that these Stomapods liave received the name of Sea-^Iantes. They were 

 named Crangones, or Crangines, by the Greeks. 



Acconling to M. Risso, they keep in deep Avater, in sandy and muddy bottoms, and couple 

 in the spring; but other species, forming our second family, bemg less favoured in res})ect to 

 their natatory a^ipendages, and having the body very flat and extended in its surface, are 

 ordinarily fouad on the surface of the ocean, -vvhere they move but slowly. 



We di\ide the order Stomapoda into two I'amilies. In 



THE FIRST FAMILY OF STOMAPODA,— 

 Unipeltata, — 

 The carapax forms unly a single shield of a quadrilaferal, elongated &bape, generally wifloned and frrc 

 behind, covering the liead (with the excejition of the eyes and antenna;, "uhich are implanted upon 

 common and frontal articulations\ and at least the anterior segments of the thorax. Its auterior ex- 

 tremity terminates in a point, and is preceded by a small plate terminating in the same manner. 7VII 

 the toot-jaws (of ^^llich the second pair is very large), and the four anterior feet, are inserted close to 

 the mouth in two lines converging inferiorly, in the form of claw-feet, with a single moveable and 

 fohled back linger. AVith the exception of the second pair of legs, all these organs are externally fur- 

 nished at the base with a small pedunculated vcscicle. The other feet, six in number, are linear, ter- 

 minated by a brush, and merely natatorial: the third joint is furnished at the side and base with a 

 slender appendage. The lateral antennae have a scale at the base, and the intermediate are terminated 

 by three filaments. The body is narrow and elongated. The ocular peduncles arc always short. This 

 family comprises the single genus 



SauiLLA (Fabr.), — 

 which we divide as follows : — 



In some species, the crustaceous shield [or carapax] is preceded by a small, more or less triangTilar, plate, situ- 

 ated above the articulation which bears the intermediate antenna; and the eyes. It does not cover the anterior 

 portion of the thorax, and is not bent down at the sides. The joint which serves as a foutstalk to the peduncle of 

 the intermediate antennae, as well as to the ocular peduncles and the exterior margins of the extremity of the 

 abdomen, is exposed. 

 .b'(7(»//« proper, L:itr., li;is the entire inner edge of the penultimate joint of the t^vo great cIciw-lVct faniii^heil 



with a narrow channel, denticuliited on one 

 side, and spined on the other; and the follow- 

 ing joint is sickle-shaped, and often toothed. 

 The type {Cancer mantis, Linn.) is about seven 

 inches long. Its great claws have at the base 

 three moveable spines; and the terminal 

 joint has sLx long and very sharp spines, of 

 which the terminal is the strongest. The seg- 

 ments of the body, except the last, have six 

 longitudinal elevated lines, ordinarily termi- 

 nating in an acute point. It is comniun m 

 the ^Mediterranean. 



Fig. 9.-SqaiUaManUs. 



Gonodacbfhis, Latr., has the channel of the great claws unarmed with points; and the ternnnal joint is dilated 

 into a knob at its base. The species are exotic. {SquUla chiragra, Fabr. ; Desmarest, pi. 4:1.) 



Coronis, Latr., has the body very narrow and depressed, with the terminal segment square and entire, without 

 teeth or spines. The lateral appendage of the six hind-legs is pallet-shaped. [C. scolopendra, Latr., regarded by 

 liim as synonymous with SquUla Eusehia of Risso ; but the figure given by this author in his Hist. Nat. Em op. 

 Merid., torn. v. pi. 4, has the terminal segment deeply toothed.] 



In the other species of this family, the carapax is slender, nearly membranous, diaphanous, entirely covering 

 the thorax, bent down at the sides, prolonged in front into an acute spine, and advanced over the stem of the in- 

 termediate antennee, and the eyes. This stem is capable of being bent downwards, and inclosed in the shield 

 formed by the curve of the carapax. The po.sterior swimmerets are hidden beneath the terminal segment. 



• Some other riniilojfous Orthopterft [suuh as thu genua Phyllium) resemble leaves. The rbylloaomce, CrustQcea of tbo same order, ei* 



