Description of Genera and Species. 79 



backward (fig. 11). They are only slightly overlapped by the wings of the carapace. 

 Their posterior margins overlap on to the epimera of the second tail segment, which are 

 directed slightly backwards and end in rounded backwardly-directed points, as do those 

 of each succeeding segment, becoming smaller and smaller successively, each being 

 overlapped by its predecessor. 



The telson is of the usual type, tumid and broad at base and flattening and tapering 

 backwards, divided into two raised areas by a central groove, and ending in a pointed 

 lobe flanked by small accessory swimmerets. Its details, taken from several specimens, 

 some of them not figured, are shown magnified in fig. 10. The eyes are moderately large 

 and placed close up to the edge of the carapace. The antennular peduncles are long 

 and not so massive relatively as in some of the other species. They are constructed of 

 the usual three joints, and end in two moderately long flagella. The antennal scale is 

 of the usual type and nearly as long as the propodite of the antennule. The peduncle 

 of the antenna is not quite so long as the scale. 



What appears to be the palp of the mandible is seen in one of the specimens pressed 

 up against the base of the antenna. The bases only of the trunk limbs are shown, but 

 in one specimen (fig. 8) an ovisac distended with either large ova or larva; is seen under- 

 lying the last two trunk segments. In this specimen the pleopods of the first four tail seg- 

 ments are also shown, and consist of the usual basal joint, which extends to beyond the 

 tips of the epimera, and the two terminal swinnning plates. The uropods are of the usual 

 type, and call for no further remark than that they extend considerably bej'ond the tip of 

 the telson. The tail fan is therefore a somewhat elegant object, as in shown in fig 10. 



Remarks. — This pretty form occurs in great abundance, and sometimes several mav 

 be seen on the same slab. As will be observed from figs. 8 and 9, which are natural size, 

 the course of the distended gut is seen very prominently. This is the general rule with 

 these fossils at the locality where they were found. Fig. 8 shows one adult female with 

 brood sack attached which also has the gut distended with food; this looks as if she 

 were in a good enough state of health when she met her death, and that she did not 

 lie long exposed before being embedded. A point, favouring the theory of wholesale 

 destruction at one and the same time, is that the remains seem to be phosphatized, as 

 also are the well-preserved specimens of Tealliocaris at Gullane. According to Sir John 

 Murray, phosphatic nodules are forming on the Aghullas Banks, where wholesale 

 destruction of fish and other forms of life often occurs through slight i^hiftin" of the 

 cold currents on to areas usually occupied by warmer water. 



In fig. 12 a magnified restoration of the parts observed of tliis C(jmpact form is given. 



Locality. — Coomsdon Burn, Kede Water, Northumberland. 



Horizon. — Calciferous Sandstone Series. 



Collector. — J. llhodes. 



