Rocky Mountains. 149 



had been found hunting in the Indian territories. These 

 men had bten liberated through the interference of some of 

 the members of the Missouri Fur Company, and had recently 

 arrived at Fort Lisa. During their captivity, they had been 



19. Tooth of a Squalus, which seems to approach nearest to those of 

 Sq. maximus, by its compressed conic form. 



Greatest length 2 1-10 inches. 

 Thickness more than 2-5 of an inch. 



The sides are rounded, without an} appearance of serratures; thicken- 

 ed near the tip, and more compressed near the base. 



20. Tooth of a Squalus, something- like that of Si gateus, but less of a 

 triangular form, and the lateral processes are more distinct, and also less 

 triangular (nan in that species. 



21. An imperfect body of a crinoid animal, Encrinite of Authors; the 

 fragment is about one half of the inferior portion of the bod), from which 

 the following description is made out, taking into view the whole circum- 

 ference. The plates composing the first costal series, (Miller) five in 

 number, are longitudinally pentangular, much curved inwards towards 

 the base, to join the first columnar ji.int, or perhaps the pelvis; at which 

 part thu plate is narrow, being about one-ninth of an inch, whilst the 

 other sides are nearly three- tenths of an inch each, the superior ones 

 being somewhat longer than the others; the second costal plates, (Miller) 

 five in number, are transversely pentangular, the superior joint being- 

 long, the lateral ones shortest, theformer being one-half an inch in length 

 the latter 3-20, and the inferior sides which articulate to the segments of 

 the pelvis, somewhat less than 3- JO of an inch; the margins of the first 

 costal joints, as well as the superior margins of the segments of the pel- 

 vis, are armed with a few tubercles, some of which seem to have been 

 perforated ; all the superior pieces are wanting in our specimen, but the 

 truncated surface, on which the scapulars (Miller) rested, is of a pentago- 

 nal outline, and composed of a series of horizontal equilateral triangles, 

 two to each side, which are separated on each side from the adjacent 

 pairs bj a deep groove, which corresponds, and is nearly at right angles 

 with thu exterior sutures, which join the first costal joints to each other; 

 these triangular surfaces, are also separated from tbe exterior edge by two 

 grooves, which are crenated, and inclose an oblong foramina between 

 them; a single intercostal, plate occurs, interposed between two of the se- 

 cond rostats, it is of an oh ong hexagonal form, its base restirg upon the 

 extremity of a segment of the first costals, which is truncated to receive 

 it, the superior portion of this plate is much bent inward towards the ab- 

 dominal cavity, its tip is quadrate and concave. 



The whole exterior surface of this rehquiurn, with the exception of the 

 tubercles, andsutural impressed lines, is plain and equable. 



If we have not mistaken the pieces of this imperfect specimen the pel- 

 vis is wanting, but the cavity in which it existed, must have been about 

 3-20 of an inch in diameter. 



Tne plate-like form of the ossicula, and their mode of articulation with 

 each other, by an extension horizontally inwards, as we have described 

 above, in the case of those plates which we have considered as the second 

 costals, seem to indicate, that this species ought to be referred to the se- 



