10 THE PEOCEEDINGS OF THE LINNEAN SOCIETY 



the fourth, but this is exactly contrary to the description of the 

 type species, Gray's Heterocyathus hemisphericus, of which it is 

 especially stated that the tertiaries are the smallest. If the 

 orders were meant the description would be still more obscure- 



The species I have to bring before the notice of the Society 

 appears to me to be one that should be referred to Psammoseris. 

 It is, however, very peculiarly distinguished by having the 

 union of the fourth and fifth orders in front of the third, and 

 the thickened lobate mass thus resulting unites again on each 

 side in front of the secondaries. It also has pseudo-pali in the 

 lobes, which spring from the septa, but they are many in number, 

 and in fact the septa alone would incline one to refer the species 

 to the Astrangiacece. The union between the septa is effected by 

 small processes like synapticulae, but the granules themselves on 

 the faces of the septa never seem to unite. The mode of junction 

 and the inclination of the septa recalls Eupsaw.midce, but the 

 wall is quite imperforate. There does not appear to be any other 

 resemblance except the junction of the septa. There is the 

 greatest difference between the various specimens in the 

 thickness and granulation of the septa. Some are so thick and 

 close that the granules almost touch, making the calicular fossa 

 seem like a regularly paved cavity ; others are thin, wavy, and 

 scarcely granular, having the rough fossa very conspicuously 

 uneven from the lobes of the septa. 



Psammoseris cylicioides. n. s. 



Corallum in general fastened to the mouth of a turriculate shell 

 (Mitra amanda, Reeve, M, hehes 8fc., an unknown Terehra, 

 and some shells, which are quite covered except at the aperture), 

 base wider than calice, and more or less constricted between, 

 and all the exterior irregularly covered with fine granules ; calice 

 irregularly circular, fossa deep and wide ; septa exsert, in six 

 systems of four cycles ; primaries with the two fourth orders 

 and secondaries with the two fifth projecting above the edge in 

 closely adpressed sets of three septa, the higher orders diverge 

 from the first and second to meet before the third, and the 



