NEOLENUS. 2 5 



(fig. 2). It is evident from the position of the notch that the row of spines was on the 

 dorsal (inner) side of the coxopodite and that the truncation was obliquely downward and 

 outward. 



The endopodite of the last thoracic appendage is well preserved and may be described 

 as typical of such a leg in this part. The basipodite is as wide as the coxopodite, and it 

 and the three succeeding segments, ischiopodite, meropodite, and carpopodite, are all parallel- 

 sided, not expanded at the joints, and decrease regularly in width. The propodite and 

 dactylopodite are also parallel-sided, but more slender than the inner segments, and on the 

 end of the dactylopodite there are four little spines, three of them one large and two small 

 articulated at the distal end, and the fourth projecting from the posterior outer angle. 

 Each segment has one or more spines on the outer articular end, and the ischiopodite has 

 several directed obliquely outward on the posterior margin. All of the four proximal segments 

 show a low ridge parallel to and near the anterior margin, and several endopodites of the py- 

 gidium have a similar ridge and a row of spines along the posterior margin of some of the 

 segments. These features indicate that the segments in question were not cylindrical in life, 

 but compressed. From the almost universal location of the spines on the posterior side of 

 the limbs as preserved, it seems probable that in the natural position the segments were held 

 in a plane at a high angl'e with the horizontal, the ridge was dorsal and anterior and the 

 row of spines ventral and posterior. Because the spines on the endobases are dorsal it 

 does not follow that those on the endopodites were, for the position of the coxopodite in a 

 crushed specimen does not indicate the position of the endopodite of even the same appendage. 



The endopodites of the pygidium are similar to the one just described, except that 

 some of them have spines on the posterior margin of the segments, and a few on the right 

 side have extremely fine, faintly visible spines on the anterior side. The specimen shows 

 fragments of a few exopodites, but nothing worth describing. In the middle of the right 

 pleural lobe there is a small organ which Walcott has interpreted as a small epipodite. It 

 is oval in form, broken at the end toward the axial lobe, and has exceedingly minute short 

 setre on the posterior margin. From analogy with other specimens, it appears to me to be 

 the outer end of an exopodite. 



Measurements: The entire specimen is about 64 mm. long and 52 mm. wide at the 

 genal angles. The thorax is about 41 mm. wide (disregarding the spines) at the seventh 

 segment, and the axial lobe about 13 mm. wide at the same horizon. The measurements 

 of the individual segments of the seventh left thoracic limb are : 



Coxopodite, 9 mm. long, 3 mm. wide, the middle of the notch 8 mm. from 

 the inner end, measured along the bottom, and 6 mm. measured 

 along the top. 



Basipodite, 5 mm. long, 3 mm. wide 



Ischiopodite, 4 3 



Meropodite, 3.5 " !' 2.5 



Carpopodite, 3.5 " 2 



Propodite, 3 " " 1.25 " 



Dactylopodite, 2 1.25 " 



The five distal segments of the last pygidial endopodite are together 10.5 mm. long. 

 The whole six segments of the endopodite of the third thoracic segments are together 21 mm. 

 long. The distance from the appendifer of the third segment to the outer end of the spine 

 is 17 mm. From the center of the notch in the coxopodite to the outer end is 1.5 mm., 



