216 BULLETIN OF THE 
into consideration, and with them the thought of the variation of the 
appendages that must necessarily correspond in a greater or less degree, 
the force of the above statement is very striking, and may equally be 
applied to the class under consideration. Such diverse forms as are 
found in the genera Asaphus, Calymene, Deiphon, Remopleurides, 
Harpes, Agnostus, and other genera, — the compact, small hypostoma 
of Ogygia Buchii,* and the long-forked hypostoma of Remopleurides 
striatulus, extending back to beneath the sixth thoracic segment,t — 
the twenty-six segments of the thorax of Harpes ungula,t and the 
two of Agnostus, — the large massive pygidium of Asaphus or Bron- 
teus and the limited area of the same in Paradowides or Remopleuri- 
des, and all the varying intermediate forms, — afford ample material for 
those inclined to theoretically reconstruct the animal, and also for the 
paleontological investigator. 
The two forms used to illustrate the results of the present investiga- 
tion are much alike in some respects, as the head and thoracic regions 
differ but little. There are certain differences, however, that are quite 
marked. The legs of Calymene are more slender, and less apt to be 
straightened out. The joints are also more cylindrical. The branchiæ 
are more delicately constructed, and usually better defined than in 
Ceraurus. Sections cut from either species are very readily distin- 
guished one from the other by the general appearance of the cephalic 
appendages, the legs, and branchiæ. 
Ova of the Trilobite. —Plate IV. fig. 8 is an illustration of a 
median, longitudinal section of a Cerawrus in which the cephalic 
cavity and a portion of the thoracic cavity are preserved and filled with 
calcspar. The small elongate-oval and round spots seen in the spar, in 
the posterior portions of the cephalic cavity and the anterior thoracic 
cavity, are somewhat enlarged in Fig. 8 a, and their arrangement 
shown as when imbedded in the spar. To the groups of ova illustrated 
by M. Barrande$ they have a strong resemblance, and there is little 
doubt but that these small cylindroid bodies were the ova of the 
Trilobite, as there is nothing to lead to the view that they are of con- 
cretionary origin.|| 
* Sil, Sys. Boh., 1. Plate 2 A, fig. 26. 
+ Cincinnati Jour. Sci., IL p. 347. 
t Sil. Sys. Boh., I. Plate IX. fig. 1. 
$ Sil. Sys. Boh., 1. Supplement, Plates 11., XVIII., and XXXV. 
| See 31st Report N. Y. State Museum Nat. Hist., Note on the Eggs of the 
Trilobite. 
