l8 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 85 



relatively smaller and more slender. Each limb has a strong proximal 

 joint (coxopodite) to which the endopodite is attached; the latter is 

 formed of four stout joints and two slender joints with two or three 

 short spines at the end of the distal joints ; the four joints between the 

 proximal and slender sixth joint may have a flattened extension on 

 the ventral side as in the endopodite of Marrella that gives them a 

 greater transverse diameter, and this may also occur in the sixth joint ; 

 the distal joint is slender and probably cylindrical ; the exopodite has 

 not been seen attached to the protopodite, but from a number of speci- 

 mens showing their position there is little doubt of their having been 

 attached as on the thoracic limb of Marrella. The exopodite is an elon- 

 gate oval, apparently unjointed lobe as seen in the specimen repre- 

 sented by figure 4, plate 17; a fringe of fine, short filaments occurs 

 on the ventral and outer margins ; the delicate structure and small 

 size makes it difficult to determine its exact nature, but as far as known 

 it recalls the exopodite of Ncolcuus. One specimen indicates that there 

 may have been an anterior support for the exopodite that extended 

 beyond the flat filamentous lobe and terminated in two minute spines ; 

 the proximal portion of the endopodites has been flaked ofif in this 

 specimen so as to expose the exopodites ; the slender distal extensions 

 may belong to the exopodites or they may be the ends of the endopo- 

 dites of the opposite side flexed under. I am inclined, however, to 

 think that they belong with the exopodites. What may be a modified 

 exopodite has been seen in one specimen ; it projects from beside tlie 

 posterior thoracic endopodite and consists of a central axis with seven 

 sharp spines projecting from its posterior side and a terminal spine ; 

 or it may be an endopodite showing the edges of plate-like joints in the 

 same manner as those of Marrella splcndeus (pi. 22, figs. 6, 7). 



Digestive organs. — -The mouth was situated at the ventral side and 

 probably bounded in front by the labrum and on the sides by the 

 mandibles ; the mouth presumal:)ly opened into a gullet that passed 

 into a large .stomach apparently divided or forked anteriorly : from 

 the rear of the stomach a straight intestine extended back to the anus. 

 A strong, relatively large tube is given ofi^ from each side of the 

 stomach at about the fifth segment; these have strong branches at 

 the proximal end, one extending forward and another backward, both 

 of which have short bifurcating branches on both the outer and inner 

 sides. In nearly all well-preserved specimens the large tube and often 

 the large connecting tul)es are rounded as thougli they were distended 

 when buried in the sediment ; this would accord with the view that 

 these were large digestive glands that contained food in process of 



