James's Account of S. H. Long's Expedition, 1819-1820, part 1

by Edwin James; Stephen H. Long; Thomas Say

Greatest length 2¹⁄₁₀ inches.

Thickness more than ²⁄₅ of an inch.

The sides are rounded, without any appearance of serratures; thickened near the tip, and more compressed near the base.

20. Tooth of a squalus, something like that of S. galeus, but less of a triangular form, and the lateral processes are more distinct, and also less triangular than 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 body, from which the following description is made out, taking into view the whole circumference. 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 joint, or perhaps the pelvis; at which part the 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, the former 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 ³⁄₁₀ of an inch; the margins of the first costal joints, as well as the superior margins of the segments of the pelvis, 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 pentagonal outline, and composed of a series of horizontal equilateral triangles, two to each side, which are separated on each side from the adjacent pairs by a deep groove, which corresponds, and is nearly at right angles with the exterior sutures, which join the first costal joints to each other; these triangular surfaces are also separated from the exterior edge by two grooves, which are crenated, and enclose an oblong foramina between them; a single intercostal plate occurs, interposed between two of the second costals; it is of an oblong hexagonal form, its base resting 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 abdominal cavity; its tip is quadrate and concave.

The whole exterior surface of this reliquium, with the exception of the tubercles, and sutural impressed lines, is plain and equable.

If we have not mistaken the pieces of this imperfect specimen, the pelvis is wanting, but the cavity in which it existed must have been about ³⁄₂₀ of an inch in diameter.

The plate-like form of the ossiculæ, 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 second division of the crinoidea, or semiarticulata of Miller. It certainly, however, cannot be at all referred to poteriocrinites, the only genus which that author has framed in this division of the family. We refrain from distinguishing it by a name either generic or specific, until other specimens can be obtained, in which the characters are less equivocal.

We have two second costal plates, which made part of distinct individuals, larger than the above described one. Of these the surface of one is perfectly glabrous, whilst that of the other has light orbicular indentations instead of tubercles; a third very small one is perfectly smooth like the first, and doubtless formed part of the body of a young individual.

Another plate found near the same spot with the above, is of a somewhat triangular form exteriorly, or rather like the face of a truncated pyramid, of which the middle of the summit is a little produced in the form of a right angle, thus offering a scollop on each side of the apex for the adaptation of superior ossiculæ. On divesting it carefully of its extraneous matrix, we discovered that it was readily adjusted by its base to the summit of those segments of the fragment above described, which we have supposed to be second costals, a prominent line on its base corresponding with the inner one of those grooves which we have described, to characterize the superior face of those plates. This plate, then, agreeably to the relations in which we have viewed the preceding pieces, must be a scapula; it is susceptible of considerable hinge-like motion, and appears to have been much less firmly attached to the costals than the latter are to each other.