Description of Genera and Species. 55 



study of the fossils are illustrated in fi^. 4, which represents the trunk and tail segments 

 of a very small specimen magnified about ten diameters. It shows plainly that the tail 

 and trunk were well marked off from each other, and that there was more play at the 

 articulation of the two than at any of those separating any other two segments of either 

 trunk or tail. It also shows the well-marked epimera upon the tail segments and also 

 the swollen pleura of the trunk segments similar to what takes place in Anaspides. 

 Only six trunk segments are seen to intervene between the division and the posterior 

 edge of the carapac(3. From the last one of these on the left side there projects the 

 portion of a cylindrical limb showing three joints, and reminding one also of the endo- 

 podites of the living form. On the same side of the body, two segments in advance of 

 that already mentioned, a structure is seen projecting beyond the segment which may 

 be the joint of an endopodite ; but it is even more like the basal joint of an exopodite 

 without the terminal swimming lash. Some detached fragments of limbs are shown 

 lying a little outside the posterolateral edge of the carapace. One of these shows the 

 last two joints of an endopodite constructed like those joints in the Lophogastrids. 



Remarks. — Notwithstanding the fact that there are only six trunk segments 

 uncovered by the carapace in this form, and that a seventh was shown to be partially 

 covered by the carapace in a specimen described by me in the original paper before the 

 Eoyal Society of Edinburgh, I still retain this form within the genus till further 

 evidence is forthcoming. This remark applies equallj' to the following species. 



Locality .—^wev Esk, Glencartholm, Langholm, Dumfriesshire. 



Horizon. — (Scottish) Calciferous Sandstone Series. 



Collector. — A. Macconochie. 



Paljeocaris landsborougiii sp. nov. PI. VIIL, figs. 8-10. 



SjJecijic Characters. — Comparatively large form. Carapace subquadrate, a little 

 longer than broad, with rounded posterior angles and slightly hoUowed out posterior 

 margin ; rostrum short and expanded at the base to form part of the eye-orbit ; trunk 

 and tail segments with median dorsal keel ; sixth tail segment long and much con- 

 stricted ; telson subquadrate or slightly shield-shaped ; uropods caridean in structure 

 and only a little longer than the telson. 



General Description. — Body 40-50 mm. long, fiattened so that it fossilises back 

 upward. The integument is thin and ^v^•inkled. 



As in P. scotira, the carapace only covers the front portion of the trunk, leaving 

 six distinct segments bare. The carapace is subquadrate, a little longer than broad, 

 and slightly narrower in front than behind. It is produced into a distinct though 



