46 Description of Genera and Species. 



of the median keel. The other keels form the raised sides and end at the sudden 

 constriction at the base of the median spine. Articulated to this constricted 

 posterior part (fig. 6) are seen two spines, one on each side, which are doubtless the 

 keels of accessory swimmerets. 



The eyes have not been with certainty observed owing to the peculiar mode of 

 fossilization already described, causing the front of the carapace to be hidden among 

 the doubled up limbs. A suggestion of their presence is shown in fig. 5 and also in fig. 

 2*, which is an enlarged drawing in outline of some of the structures seen in specimens, 

 of which fig. 2 is natural size. The last two joints of the peduncles of each of the 

 antennules are also shown somewhat displaced. The terminal joints in each case bear 

 the usual two lashes, the external one being somewhat the larger and longer, though they 

 are both small compared with the lashes of the antennas. The position of the body of 

 the mandible is almost invariably shown by a collapsed area near the antero-lateral 

 border of the carapace, showing that the head organs are in direct connection with the 

 carapace. In fig. 2**^ a three-jointed limb-like organ is seen to pass forwards from the 

 collapsed body of the mandible, but it appears to be too massive to be the palp of that 

 organ. It is more probably three joints of one of the more anterior of the legs, or possibly 

 the maxillepede. The same enlarged figure shows the nature of some of the endopodites 

 of the appendages of some of the last seven trunk segments, which are very massive and 

 laterally compressed. The tip joints are spatulated; the succeeding joint is short and 

 subquadrate; the third joint is long and bent upwards and strengthened by longitudinal 

 lateral keels. The articulations of these joints flex backwards. Succeeding the long 

 thin joint there is a fourth which is short and subquadrate; the articulation between the 

 third and fourth joints flexes forwards. The limbs cannot be traced any further inwards 

 with certainty. The long so-called thin joint ui all probability corresponds with the 

 iscliiopodite, in which case this limb would flex in the same manner as in xVnaspides (pi. 

 viii., fig. 11). Short fragments of many -jointed exopodites are to be made out among the 

 broken-up debris of limbs. What appear to be gill filaments can also be seen at the junc- 

 tion of the sternites with the tergal portions of some of the trunk segments, and an organ 

 lying detached is highly suggestive of a brood pouch. Fig. 4 shows what appear to be 

 the basal joints of six of the exopodites on one side, still attached to their respective 

 segments, and a seventh that has broken away. The endopodites are all flexed in the usual 

 way and crowded and crushed upon each other. Figs. 2'^ and 5 show what are probably 

 the eyes in place, the crushed mandibles, and the folded legs, flexed in the usual manner 

 and crushed up together. Of the tail appendages, only the uropods have been observed. 

 These are very much as in /*. stocki, only the basal joint appears to be proportionately 



