1854.] 



NEW GENERA AND SPECIES OF.CYSTIDEA. 



269 



aperture a little below. That genus, however,, was unprovided 

 with arms, and had six plates in the pelvis. In this there are but 

 three plates in the pelvis, and besides it bears upon its summit 

 certainly three, if not four, long tentaculated arms. In other re- 

 spects it is nothing more than an elongated Spheronite. 



The arms are each composed of a single series of large oblono- 

 joints loosely articulated upon each other. From each joint pro- 

 ceeds one long nearly cylindrical tentaculum, also composed of a 

 single series of short joints. The large specimen, fig. 3, is deeply 

 buried in a piece of limestone, and as only one side of the arm is 

 above the surface, it cannot be determined whether another row 

 of tentacula exists on the other side of it or not. 



The tentacula are not perfectly cylindrical, but compressed to a 

 sharp edge on one side, and on each side of this ridge a row of 

 obscurely visible pits extends the whole length, as if here an 

 appendage of some kind had been fastened. 



The other specimen (Fig. 1) is detached from the matrix, and 

 preserves its form, with the exception of a very slight compression. 

 The summit shows the bases of three arms. Two of these are 

 placed close together on the edge of the summit immediately over 

 the ovarian aperture, and the other upon the side opposite. The 

 summit is not circular, but elliptical, the pair of arms standing at 

 one end of the ellipse and the single arm at the other. 



Professor Forbes has figured three Cystideans from the Bala 

 limestone of Shole's Hook and Reulas, with protuberances upon 

 their summits very like the bases of the arms remaining on several 

 specimens of this species. Of two of these, of the same species, 

 Caryocystites munitus, he says, " They are both globular bodies, 

 nearly smooth, except for the markings referred to, and especially 

 distinguished by their summits being crowned with four tubercles, 

 connected together by ridges, so as to form, as it were, a turretted 

 wall and square fortification around the mouth." (Memoirs of 

 the Geological Survey of England, Vol. 2, part 2, page 515, and 

 plate 21.) The appearances exhibited by the fossils found here, . 

 when compared with Professor Forbes's figures, strongly induce 

 the suspicion -that some of the English Cystideaa were also pro- 

 vided with free arms. 



It may be observed here that Von Buch was of opinion that 

 the Cystidea were totally destitute of arms. Voborth supported 

 the opposite view, and contended that they not only had arms 

 like the Crinoidea, but that they were in fact true Crinoids. 

 Afterwards several species were discovered with flattened appen- 

 dages, which were turned downwards from the summit and at- 

 tached to the sides, as in Glyptocystites multipara. Another, 

 Prunocystites Fletckeri, was found at Dudley, in England, with 

 the remains of several long tentacula, like those of the genus 

 Pleurocystites. Professor Forbes describes it as " a small ovate 

 cystidean, with a very large stem attached, and presenting the 

 remarkable feature of possessing long tentacula, or filamentary 

 arms, not folded back and lodged in grooves, as in the Pseudo- 

 crinites and its allies, but projecting directly from the oral aper- 

 ture, around which they appear to have been attached. . . . 

 They appear to be analagous to the Angel's and not the arms of 

 Pseudocrinites" (Mem. Geo. Sur., page 503 and 504.) The 

 specimen (fig. 3) is probably the first ever discovered with a true 

 tentaculated arm rising free from the summit. It is not, however, 

 on account of its being furnished with free arms, a Crinoid. In 

 animals of this latter order the ovaries are said to have been borne 

 aloft upon the arms and the eggs protected by the tentacula until 

 the proper time arrived for casting them off; but in the Cystidea 

 2 



the organs of reproduction, according to the opinions of many of 

 the best naturalists, open out to the exterior through the largo 

 aperture in the side beneath the summit. 



It has been stated that the summit of this fossil is elliptical, and 

 that a pair of arms stands at one end of the ellipse, and a single 

 arm at the other. From the single arm a deep groove now filled 

 with dark calcareous matter is seen in the specimen (Fig. 1) to 

 extend to a point between the other two. This is without doubt 

 the mouth. It follows the major axis of the ellipse, and is there- 

 fore elongated in an anterior and posterior direction, that is to 

 say, it extends from a point directly over the ovarian aperture 

 straight across the summit to the opposite or anterior side. There 

 is some evidence to show that from the ends of the mouth 

 grooves extend up the arms on the inside, as in the Crinoids ; but 

 the specimens are not sufficiently cleared of the matrix to deter- 

 mine this point with certainty. Neither do they show positively 

 that in any case there were only three arms. It appears to me 

 that there must have been a pair at each end of the mouth, and 

 that in some instances one of them has either been removed or 

 cannot be seen. In the huge specimen figured the arm is well 

 preserved, but -the upper part above theMrinth joint is buried in 

 the stone, so that its length cannot be determined. 



On the right of the summit of the specimen Fig. 3 the impres- 

 sion of the other arm of the pair remains. These two arms 

 appear to be placed further apart than in some other specimens. 



The column is round* and composed of thin joints, so that it is 

 nearly smooth, or only surrounded by very small rings close to 

 each other. 



Many specimens of this fossil in a more or less fragmentary 

 condition, have been found by different persons within the last few 

 years in the Trenton limestone of this locality, generally along the 

 water's edge from the Rideau falls to the Chaudiere. As neither 

 the pelvis nor arms were preserved in any o! these that came within 

 my observation, I always supposed them to be portions of a new 

 - species of Spheronites, judging from the great, number of plates. 

 At length, in the month of June last, I had the good fortune to 

 discover the magnificent specimen (Fig. 3) in a place where it is 

 strange that it had not been previously detected. A large pic- v 

 nic party once assembled on this spot, and, as I am informed, the 

 gentlemen and ladies danced upon the level surface of the lime- 

 stone rock without discovering the sleeping form of this ancient 

 inhabitant of the old Silurian ocean. This was ten years ago, and 

 it is possible that during the period which elapsed the fossil be- 

 came more exposed by the weathering of the matrix. During 

 the last autumn I collected several others, not so perfect, but exhi- 

 biting parts not exposed in this specimen. Fig. 1 was found in 

 the month of November last, by Mr. W. S. Hunter of this place, 

 from whom I procured it. Nearly all the specimens that I have 

 seen are unquestionably of the'same species as this Fig. 1, and I 

 have therefore selected it as the typical form. From its shape 

 and the appearance of its surface, 1 beg to suggest as a name for 

 the genus, Comarocystites, from the Greek Kopagov — a straw- 

 berry. Its characters may be concisely summed up as follows : — ■ 



GENUS COMAROCYSTITES. 



(Greek KOjiapov, arbutum, and kvotic,, vesica.) 



. Body ovate, the smaller extremity being the base, pelvis small, 

 of three plates, above which are from eight to eleven rows of 

 plates, mostly hexagonal, ovarian aperture near the summit, closed 

 by a valvular apparatus, mouth apical, arms free, composed of a 

 single series of joints and bearing tentacula, column round. 



