34- GEOLOGICAL MEMOIRS. 



depressed mouth may be readily distinguished (a), but the anal 

 orifice {d) is more difficult to find. On the plates are ambulacral 

 pores arranged in rows, about six in each row, from the centre 

 towards the angles of the plates, as in Hemicosmites. We are 

 not at present acquainted with the details of the law of their distri- 

 bution. 



Hisinger has united this species with the former under the name 

 Sphceronites testudinarius, but since he has not given the reasons 

 which induced him to abandon the older name, S. granulatum 

 (adopted by himself from Wahlenberg, and given from the resem- 

 blance of the fossil to crystals of garnet), I have thought it better to 

 apply his name to this remarkable species which he has considered as 

 a variety. 



Locality, Bodahamn in Oeland. 



Genus HEMICOSMITES. 



5. Hemicosmites pyriformis, v. Buch. \Echinosph(BriUs ma- 

 lum^ Pander, tab. 29. fig. 1, 2, 3, where the position is inverted, 

 the stem being above and the mouth below. Hemicosmites pyri' 

 formis, v. Buch, Beitr. z. Best. d. Gebirgsform. in Russl. tab. 1. 

 figs. 1 to 3, 6 to 8, 11 and 13.] 



Plate III. fig. 6. 



It cannot be denied that there is considerable resemblance be- 

 tween this genus and Caryocrinites, but the manifest absence of 

 arms separates it entirely from the Crinoidea, while the large ovarial 

 orifice at the side [PI. III. fig. 6. (h)'\ brings it into close relation 

 with the other Cystidea. 



Here again the pelvis is composed of four plates, two of them 

 pentagonal and two quadrilateral, which by the bisection of the 

 larger ones form six similar plates. Six large long plates form the 

 side of the cup, and so symmetrically that they divide the whole into 

 two dissimilar halves, in each of which the plates have a distinct 

 form. The three which rest upon and between the two pentagonal 

 plates are hexagons, each terminating upwards in an angular point, 

 and two of them include in their upper half the large ovarial orifice, 

 which is closed with five valves. In the opposite half, however, each 

 lateral plate has its upper angle truncated, and thus from a hexagon 

 becomes a heptagon. An upper row of six plates, corresponding to 

 scapulars, incline inwards to form a dome-shaped vault, and termi- 

 nating in a wedge-like manner they embrace the mouth. On that 

 side on which the plates are truncated, but not on the other, there 

 are three additional smaller plates inserted above the truncated angles 

 in a direction towards the mouth. 



The mouth is placed in the middle of the summit on a somewhat 

 projecting proboscis covered with small plates. It appears as if this 

 proboscis separated itself into three parts, which must have been 



