116 F. R. C. Reed— New Crustacea, Isle of Wight. 



Thenops Carteri, sp. nov. (PL YII, Figs. 2, 2a.) 



Description. Carapace elongated, narrowing anteriorly, divided at 

 about half its length by cervical groove; median dorsal portion of 

 carapace flattened, especially in thorax, with lateral portions bent 

 down steeply on each side along tuberculated longitudinal lateral 

 carinas. 



Cervical groove deep, strongly marked, divisible into (1) a short 

 middle transverse portion slightly arched forwards and about one-fourth 

 the width of the carapace at this level, and (2) a pair of lateral 

 portions bent sharply forwards on each side and running out so as to 

 meet the lateral carina? at about 45°, outside which they bend down 

 almost at right angles to inferior edge of carapace but turn forwards 

 close to margin to meet it at an acute angle. 



Posterior end of carapace concave in outline, and furnished with 

 a narrow rounded ring with pitted surface marked off by a strong 

 smooth furrow. 



Cephalic portion of carapace with upper surface very gently convex, 

 and denned on each side by slightly curved, fine lateral carinas diverging 

 backwards from rostral teeth to cervical groove, and marked b) - row of 

 small sharply pointed tubercles increasing in size posteriorly. 



Anterior end of cephalic portion abruptly truncate, furnished with 

 median pair of short triangular rostral teeth somewhat flattened with 

 their faces inclined inwards and their points about one-third the 

 anterior width of the carapace apart. Median notch between rostral 

 teeth rounded. Anterior edge of carapace outside rostral teeth simple, 

 nearly straight, not excavated nor dentate, .meeting lateral edges 

 nearly at right angles. Median portion of cephalic region forming a 

 slightly elevated sub-lanceolate pre-gastric area, ill-defined at the sides 

 and behind where at about half the length of the cephalon it touches 

 two sub-parallel, gently curved longitudinal rows of 6-7 spinose 

 tubercles, bounding laterally the narrow, elongated, somewhat flattened 

 gastric region reaching back to the cervical groove and having a width 

 equal to about one-fifth that of the base of the cephalon. 



A pair of low indefinite longitudinal ridges run back from the bases 

 of the rostral teeth with a slight divergence to the level of the 

 anterior end of the gastric region, where they end in somewhat marked 

 depressions, prolonged outwards as weak grooves curving back to the 

 lateral carinas and marking off indistinctly on each side of the gastric 

 region a sub-triangular area in front of the cervical groove. Outside 

 the lateral carinas of the cephalon the carapace is bent down, very 

 slightly at the anterior end, but with increasing steepness posteriorly. 

 Inferior edge of carapace thickened and armed with large closely set 

 spinose tubercles. 



Thoracic portion of carapace with upper part horizontally flattened, 

 but medially somewhat elevated into cardiac region and bearing 

 a longitudinal carina of large pointed tubercles. Cardiac region with 

 slight independent swelling, about two-thirds the length of thorax 

 and one-third its width, sub-lanceolate in shape and marked out on! 

 each side by weak furrows gently curved, but not defined behind. 

 On each side of cardiac region thorax is flattened and horizontally 



