The Invertebrate Fauna of the Uitenhaye Series. 213 



carapace it is deeply impressed. Traced from its anterior termina- 

 tion, for the first few millimetres of its course, immediately under 

 the lowest cephalic keel, it has a very slight upward inclination ; it 

 then bends more sharply upwards, and during the rest of its course, 

 towards the median dorsal line of the carapace, it is not markedly 

 sinuous. 



Immediately behind the cervical suture there is on either side a 

 short raised keel in backward continuation of the lowest lateral 

 cephalic keel ; this is only a few millimetres in extent (about 5 mm. 

 in specimens examined), and immediately below it is situated a small 

 oval area, nearly smooth, bearing only one or two isolated granules, 

 and surrounded above and below and behind by a well-impressed 

 linear groove. In the specimens examined this is only about 2 mm. 

 or 3 mm. in length, but is not well defined anteriorly. From this 

 little area the weakly developed branchial furrow passes obliquely 

 backwards, rising gradually, and dies out before reaching the 

 indented portion of the posterior margin of the carapace. This 

 furrow is bounded dorsally by a slightly raised fold of the surface, 

 which arises anteriorly at the short keel which forms the backward 

 continuation of the lowest cephalic keel. 



The median dorsal carination is a very marked feature, posteriorly 

 to the cervical groove. Commencing at the median carina at a dis- 

 tance from the cervical suture of about one-third of the space between 

 that suture and the posterior margin of the carapace, there is a very 

 faintly marked, shallow linear groove of attenuated sigmoidal form. 

 Meeting the corresponding groove of the opposite side in the median 

 dorsal line so that no appreciable angle is formed by the junction, 

 the groove on each side of the carapace forms a shorter shallow 

 upper curve and a more extensive lower curve. Before terminating 

 below it is for some distance directed anteriorly, and runs obliquely 

 downwards just above the fold of the surface which accompanies the 

 branchial furrow. 



The lower margin of the thoracic part of the carapace is divisible 

 into a shorter antero- ventral portion, which slopes gently downwards 

 with straight outline when traced backwards, and a longer posterior 

 portion with almost straight outline, which slopes gently upwards 

 and then passes by a broad curve into the posterior border. The 

 posterior border forms in its lower part, a broad lobe with convex 

 outline, and is then indented (between the branchial and cardiac 

 regions) in the shape of a narrowly curved bay with broad 

 opening. 



The margins of the thoracic portion of the carapace are furnished 



15 



