50 CALAMOCEINUS DIOMEDiE. 



Figures *J and 3. Plate KXVIIL. give an asymmetrical view of the three 

 incomplete joints which go to form the spreading base, as seen from the 

 curved side of the stem. Figure 4 shows the same joints seen from the 

 convex side of the curved stem. The line of separation between the ex- 

 panded base and the joints is very distinct. The expanded stem joints 

 forming the base of the stem of Calaraocrinus bear a striking resemblance 

 to the root of Anomaloerinus incurvus figured by Meek (Geol. Survey of 

 Ohio. Palaeontology, Vol. 1. Plate 2, Fig. G' 1 ). 



The diameter of the piece of the stem collected in 1801 is 10 mm. at 

 the third ring above the basal expansion (Plate XXVIII. Fig. 2). From 

 that point there are six rings to a length of 10mm.; about one third 

 of the length from the base there are ten rings to a length of 10 mm.; 

 and near the extremity of the piece figured, where the diameter is reduced 

 to 4 mm., there are twelve rings in a length of 10 mm. 



Figure 5, Plate XXVIII., shows the upper part of the stem with the 

 wedges of the new arm joints intercalated between the older joints. From 

 the size of these new joints near the summit, this specimen must have 

 been an old one, as it shows no trace of the young joints indicated by 

 narrow wedges in the other specimens figured. This older specimen shows 

 also the peculiar disconnected intercalated stein joints figured in many 

 fossil species. 



The longest piece of stem was ISO mm., with a diameter at the large 

 end of 5.30 mm., and at the small end of 4 mm. About 110 mm. of this 

 is straight, the rest slightly curved towards the large end, much as in 

 Figure 8, Plate XVII. At the smaller extremity sixteen joints measured 

 2o mm. in height; near the middle of this fragment of stem ten joints 

 measured 10 mm. in height, and at the larger extremity sixteen joints 

 measured only 10 mm. in height. The serrations of the articulations are 

 quite distinct near the wide end. The ridges of alternating joints gradu- 

 ally disappear, towards the first quarter of the stem only every fourth 

 or fifth joint has a slight ridge, and towards the lower third of this part 

 of the stem these ridges disappear entirely and the joints become smooth, 

 the serrations disappearing at the same time. 



A fragment of a stem, shown in Plate XVIII. Fig. 2, is 70 mm. long, 

 with the upper end crushed. Twenty joints to 11mm. at the top; in the 

 middle, twenty-four joints to 10 mm.; below this, eighteen joints to 13 mm.; 

 and at the bottom, thirteen joints to 13 mm. The diameter of the upper 



