96 



S. 560—24 X '07. 15 mis. W. S. W. of Chicken Rock, Isle of 

 Man, 38J-42 fms. Trawl. — Four, 44-40 mm., 3 

 ovigerous. 



S. 561—24 X '07. 12 mis. W. by S. of Chicken Rock, Isle of 

 Man, 34-38 fms. Trawl. Temp., at 30 fms., 12-75° C. 

 Salinity 34.04 °/^^. — Seventeen, 44-14 mm., 2 ovi- 

 gerous. 



Family LAOMEDIIDAE. 



Genus Jaxea, Nardo. 



Jaxea noctuma (Chiereghin) Nardo. 



PI. XV, figs. 1-8, 



Cancer nocturnus, Chieregliin, 1818. 

 Jaxea noctuma, Nardo, 1847. 

 Calliaxis adriatica, Heller, 1863. 

 Trachelifer (juv.) Scott, 1899. 

 Jaxea noctuma, Scott, 1900. 



The carapace is laterally compressed and considerably shorter 

 than the abdomen. It is covered with a fur of short setae, 

 which are most densely crowded on the cardiac area. There is 

 a very distinct linea thallassinica on each side of the carapace, 

 which is thus divided longitudinally into three parts. The 

 middle and dorsal part is almost smooth, and projects anteriorty 

 to form the sharp triangular rostrum, which is furnished with 

 very fine teeth on either side. The upper surface of the rostrum 

 is hollowed out, but this depression is not continued on the 

 carapace proper. The lateral parts of the carapace are slightly 

 inflated, and are covered with little tubercles which are most 

 numerous near the lower margin. On the front margin there 

 are three or four small teeth immediately below the beginning 

 of the linea thallassinica. The anterior margin merges gradually 

 into the lateral one without any sharp angle. The cervical 

 groove is deeply marked, and does not cross the linea thallassinica. 

 The posterior margin of the carapace is strongly concave, and is 

 overlapped on each side by a short process of the first abdominal 

 segment. The carapace is broadest about the middle of the 

 cardiac region, and narrows slightly before and behind this. 



The abdomen is longer than the carapace, and is of uniform 

 breadth throughout. The terga are quite smooth, and bear a 

 fairly thick covering of very short setae, set close together. 

 The pleura of the first segment are sharply triangular, those of 

 the other segments broadly so ; they have a small projecting lobe 

 on the posterior margin, except in the first and sixth segments. 

 The anterior edge of the first pair of pleura bears three or four 

 small teeth. On the following segments, both anterior and pos- 

 terior edges of the pleura bear a number of very minute den- 

 ticules, but these are apparently absent altogether in some cases. 



The telson is quadrate, and its distal part is not so strongly 



