Genus Latreutes Stimpson, 1860 



Stimpson, 1860, p. 27.— Hemming, 1958b, p. 157. 



KEY TO SPECIES IN THE CAROLINAS 



a. Carapace and rostrum unarmed dorsally except for a 

 single, small, median spine on gastric region ; rostrum 

 an elongate blade nearly as long as carapace 



fucorum (p. 78). 



aa. Carapace strongly humped and armed dorsally with 

 five or six spiniform teeth ; rostrum a deep ovoid blade, 

 shorter than carapace parvulus (p. 79). 



Latreutes fucorum (Fabricius) 



Figure 63 



Palaemon fucorum Fabricius, 1798, p. 404. 



Latreutes ensiferus: Hay and Shore, 1918, p. 390, pi. 26, fig. 13. 

 Latreutes fucorum: Verrill, 1922, p. 131, pi. 16, figs. 5-5b ; 

 pi. 42, figs. 2-2t ; pi. 44, figs. 1-lm, 2a-2n, 3 (rev.). 



Recognition characters. — Rostrum thin, nearly 

 as long as carapace, smooth edged, broadest at 

 base and deepest near base, slightly concave 

 dorsally and upturned at tip, convex ventrally; 

 tip subtruncate and armed with about five to 

 seven small, acute spinules. Carapace smooth; a 

 small middorsal spine on gastric region; anterior 

 margin produced into an acute lobe below eye 

 followed ventrally by a wide, nearly rectangular 

 emargination and a series of four to nine small 

 denticles at anterolateral angle; a spine removed 

 from margin near suborbital lobe. Eyes well de- 

 veloped, with a tuberculate swelling antero- 

 medially near cornea. Antennular peduncle with 

 basal article excavate laterally ; stylocerite broad, 

 thin, cupped dorsally; distal spine on lateral 

 border of basal article reaching about to base of 

 third article; second and third articles short; 

 distal border of third obscurely denticulate, outer 

 flagellum thick at base. Antennal peduncle stout; 

 antennal scale wide at base, tapering to acute ter- 

 minal spine, scale about as long as rostrum. Third 

 maxilliped elongated, leglike; distal article long, 

 with eight or nine acute marginal spines. 



First legs incurved, short, relatively stout, un- 

 equal ; larger chela thick, proximally broad, ovate, 

 tapering distally ; dactyl wide, longer than immov- 

 able finger, with broad lateral lobe and about three 

 denticles at tip; immovable finger bent slightly 

 inward and arched, tip subacute or slightly biden- 

 tate; fingers hairy; carpus large, cup-shaped, 

 broader than long; merus and carpus excavate 

 beneath. Second legs slender; chelae slender, 

 somewhat unequal ; fingers about as long as palm, 



hairy at tip; carpus with three unequal joints, 

 middle one longest. Third to fifth legs long, 

 slender, subequal; propodi and dactyls with row 

 of spines on lower edge. 



Abdomen smooth. Telson long, narrow, taper- 

 ing to narrow tip with spiniform median process 

 flanked by two pairs of unequal spines, inner pair 

 longer than median process; two pairs of dorsal 

 spines, at half and three-fourths of length. 

 Uropodal exopods with outer edge terminating in 

 a small sf>ine flanked medially by a movable spine. 



Measurements.— Length of body: adults, 12 to 

 20 mm.; males smaller than females. 



Variations. — The rostrum varies greatly in 

 length, depth, and number of spines (Wass, 1955). 



Figure t>3. — Latreutes fin-mum (Fabricius). A, animal 

 in lateral view, x 17 (after Bate, 1888) ; B, antennal 

 scale, X 17; C, distal article of third maxilliped, X 42; 

 I). right first cheliped. X 17: E, left first cheliped, X 

 25 : F, second cheliped : X 17 : (i, distal articles of third 

 leg. x 1"; II, telson and uropods, X 17 (after Verrill. 

 1922). 



78 



FISH AND WILDLIFE SERVICE 



