38 GEOLOGICAL MEMOIRS. 



the stem is placed, and diametrically opposite the diamond-shaped 

 set of pores on the basal plate. 



The ridges which surround the opening very often rise so high 

 that they project far above the side, in the manner of a proboscis ; 

 but that it is a true ovarial opening and not an anus, as it has been 

 often considered, appears clear from what is observed in the Sphse- 

 ronite and Caryocystite, where the mouth is always accompanied by 

 an exactly similar smaller aperture adjacent, invariably acknow- 

 ledged as the anus, and in the allied forms this aperture is in no 

 case far removed from the mouth, while sometimes, as in Pentre- 

 mites, it is actually placed within that cavity. Such may also be 

 the case in Sycocystites, 



It is a question whether Sycocystites striatus (Pander, tab. 2. fig. 30, 

 31. tab. 28. fig. 12) ought to be considered a distinct species or 

 merely a variety of the foregoing. It is of the form described and 

 figured by M. von Meyer, and in all essential points the two are 

 identical, even with regard to the remarliable and strilting diamond- 

 shaped rows of pores, but the plates are covered with a larger num- 

 ber of striae at right angles to the edges, and these striae are not so 

 prominent. In this so-called aS'. striatus^ which attains a larger size 

 than the species above described, there are ten or twelve striae on 

 every rhomb, and as many as fifteen in that marked by pores. The 

 larger species is evidently the same as that described and badly 

 figured by Schlottheim in the "Isis" for 1826 (Heft iii. tab. I. 

 fig. 1), the identical specimen having been before described by Von 

 Meyer in January 1825. Schlottheim erroneously calls it Echino- 

 sphcerites granatum, Wahl., and others have without examination 

 repeated this mistake. 



Both species have been found hitherto only at Pulcowa near St. 

 Petersburg. 



Genus CRYPTOCRINITES. 



7. Cryptocrinites cerasus, Von Buch. {^Echinosphcerites IcBvis, 

 Pander, p. 147. tab. 2. fig. 24-26. V. Buch, Beitr. z. Best. d. 

 Gebirgsform. in Russl. p. 36. tab. 1. fig. 4, 5, 9, 10, 12. Sycocri- 

 nites Jacksoni et anapeptamenus, Austen, Annals of Nat. Hist. 

 1843, vol. xi. p. 206.] 



Plate III. fig. 8. 



Form nearly spherical, but somewhat swelled out in the lower 

 hemisphere. Three plates surmount the slender pedicle, two larger, 

 pentagonal, and one smaller, rhomboidal. As is the case invariably 

 in the Cystidea, the two pentagonal plates bisected become each of 

 them a pair of equal and similar rhomboidal plates. 



Of lateral plates there are, first, a row of five, two of them placed 

 on the bases of the two pentagons and the others touching two sides 

 of adjacent plates. Five other plates alternating with these com- 



