Description of Genera and Species. 49 



never been recognised owing to the habit so often referred to, and for the same reason 

 the maxillas and maxilHpedes have not been recognised. The endopodites of the legs 

 are all thrown forward and huddled together. The details of each appear to be much 

 as in the other species, for the long upwardly-curved massive joint is conspicuous in all 

 the specimens. In fig. 1 a fifth joint from the tip is seen in addition to the other four 

 observed. This shows that the fourth is short, and that at the articulation with the fifth 

 the limb flexes forward. Figs. 1, 2, and 5 all show a row of short joints, in which the test 

 is not as dense as in the legs, which are directed downwards and slightly backwards, and 

 which overlap the shorter proximal joints of the legs. They strongly suggest that they 

 are the basal joints of the exopodites, and in fig. 5 there are structures folded upwards 

 and forwards suggestive of their terminal swimming lashes. In fig. 1 the bases of 

 these joints are obscured by fimbriated bunches which are strongly suggestive of gills. 



The pleopods (figs. 1 and 2) have massive basal joints which extend beyond the 

 edges of the epimera, and support leaf-shaped jointed swimmerets. There is no 

 evidence to show whether the first two pairs of pleopods were modified in their inner 

 branches for sexual purposes. Such evidence as the imperfectly preserved pleopods 

 afford is rather against the presumption that anything like the tufts of filamentous 

 gills that occur in the Squillids could be present without being observed ; but the 

 evidence either for or against it is not of much value. The uropods, constituted very 

 much as in the two former species, are shorter relatively to the telson than in either 

 of them. The basal joint is longer proportionately than in P. stocki and shorter than 

 in r. elegans. 



Locality. — Eiver Esk, Glencartholm, near Langholm, Dumfriesshire. 



Horizon. — Scorpion bed. (Scottish) Calciferous Sandstone Series. 



Collectors. — A. Macconochie and T. Stock. 



Perimecturus ensifer sp. nov. PL VIL, figs. 8-14. 



In the collection of the Scottish branch of the Geological Survey there are the 

 remains of crustaceans belonging to this group which were obtained by Mr. 

 Macconochie from the Cementstone group of the Calciferous Sandstone Series of 

 Liddesdale, a somewhat lower horizon than the Eskdale scorpion bed. Some of these 

 specimens were figured and described by Robert Etheridge, junior, in 1879,' and doubt- 

 fully referred to the Phyllocarid genus DitJiyrocaris. The whole construction of the 

 tail, with its epimera, telson, and urojwds, shows that the form belongs to the present 



' U. Etheiiilge, Juii., Quart. Journ. Geol. Sop., vol. x.xxv., p. 404, pi. xxiii. 



