380 PROCEEDINGS OF THE NATIONAL MUSEUM. vol. xxxm. 



DINEMATURA PRODUCTA Miiller. 



Plate XXIII. 



Caligus productus Muller, 1785, p. 132, pi. xxi, figs. 3 and 4. 



Dinemoura producta Latreille, 1829, p. 197. 



Pandarus lamnse Johnston, 1835, p. 203, fig. 22 (text). 



Dinemoura lamx Baird, 1850, p. 286, pi. xxxiii, fig. 8. 



Nogagus productus, Gerstaecker, 1853, p. 63, pi. iv, figs. 1 to 10. 



Dinematura elongata Van Beneden, 1857, p. 226; 1860, p. 149, pi. xxiv. 



Dinematura producta Steenstrup and Lutken, 1861, pp. 371, 374, pi. vii, fig. 13. 



Female. — Carapace orbicular, a little wider than long; frontal 

 plates wider and more prominent than in. ferox, their anterior margin 

 nearly straight, with a deep and well-defined central sinus. 



Lateral areas wide, their transverse grooves far in front of the pos- 

 terior margin of the carapace and making only small indentations 

 on the lateral margins; posterior lobes short and wide, and curved 

 inward strongly at the tips. Eyes not visible in any of the specimens 

 examined. Free thorax segments very short but wide, filling the 

 entire space between the posterior lobes of the carapace. Lateral 

 plates on the second segment short and oblique; no plates on the 

 third segment; those on the fourth segment narrow and nearly as 

 long as the carapace on the mid-line, being more than twice as long 

 as wide. Together, these plates are no wider than the genital seg- 

 ment, and are evenly rounded at their anterior corners, not projecting 

 as in ferox; the posterior ends are also evenly rounded, wliile the 

 median sinus extends about three-fourths the entire length and is 

 somewhat enlarged at its base. 



Genital segment oblong, a little more than half the width of the 

 carapace, with short and rather narrow posterior lobes; dorsal plates 

 covering this segment a little narrower and shorter than the segment 

 itself, as in ferox. Their posterior ends are cut off obliquely but in 

 a direction opposite to that of ferox, leaving a sharp corner at the 

 imier, instead of the outer, angle; median sinus wide, fairly deep, 

 and wedge-shaped, with a squarely cut base. Dorsal process of the 

 sixth segment narrow and elongate, reaching far behind the genital 

 segment and abdomen; dorsal plates covering the process also narrow 

 and elongate, not quite as long as the process itself, divergent, and 

 separated by a triangular sinus two-tliirds of their entire length. 



The base of this sinus is opposite the tips of the dorsal plates on 

 the genital segment. Body of the sixth segment short and about 

 the same width as the abdomen; sixth legs large and somewhat boot- 

 shaped, with the heels turned outward. They reach back to the 

 tip of the dorsal process, are armed with rudimentary spines like the 

 fourth legs, and are plainly visible in dorsal view. Abdomen small 

 and subquadrangular, projecting beliind the genital segment, but 

 entirely concealed in dorsal view by the process, legs, and dorsal 



