202 Mr. H. J. Carter on a new Genus 



in its cavity transversely by reticulated rugaj of the same 

 material, whicli, in prominent relief, hanging down from the 

 roof, produce an extremely irregular surface, owing to the large 

 grains of sand of which the ruga? are comj)osed, hut the whole 

 rendered smooth by sarcodic lining throughout ; presenting a 

 row of large apertures on each side, about the same size as, and 

 arranged in a similar manner to those on the convexity of the 

 exterior of the last-formed chamber {f\g. 4, h h), which, as 

 the latter is successively added, become the septal holes of 

 intercameral communication (tig. 5, a) ; also presenting a 

 great number of smaller holes varying in diameter below 

 2-lSOOths inch, situated respectively in the deep interstices of 

 the reticulated rugaj hanging from the roof (fig. 4) ; leading 

 to equally irregular passages diminishing in size and some- 

 times branched as they extend towards the surface of the test 

 (fig. 6, c, fig. 5, h, and fig. 7, e), where they appear to open in 

 points not larger than l-20,000th inch in diameter ; at least 

 such is the measurement of the closed dry and retracted sar- 

 codic lining viewed in the latero-vertical section close to the 

 surface, although the crevices among the sand-grains through 

 which these points probably opened caimot themselves be 

 recognized on the surface itself; floor of the chamber also more 

 or less similarly foraminatcd and sulcated like the roof. 

 Cavity of chamber often containing brown fragments of ag- 

 glomerated sarcode and sponge-spicules. Size of entire speci- 

 men variable, the largest which I possess being about l-6th 

 inch in diameter and rather longer than broad (fig. 2). Cham- 

 bers very variable in length below l-60tli inch, and equally 

 variable in transverse diameter below the same size. 



Hah. Marine, in excavations on the surface of a large glo- 

 bular mass of Siderastrcea. 



Loc. ? Coral reef. 



Ohs. The general form of this Foraminifer is, in miniature, 

 that of a group of sucking, half-filled leeches on the human 

 skin, hence the name (/SSeWa) ; and the com})osition of the 

 test, consisting exclusively of calcareous material and fragments 

 of siliceous sponge-spicules, seems to indicate that the coral 

 on which the specimens v\-ere found grew on a "reef" where 

 silex in no other shape could be obtained. 



There is no doubt from this composition that it belongs to 

 the Lituolida, or to that portion of the Arenaceous Foraminifera 

 which hitherto have been considered " imperforate," simply be- 

 cause no pores on the su.rface could be detected by the micro- 

 scope. The same might be said of the frustules of the 

 Diatomacea3 even during active life, when they are in con- 

 tinued motion — with much more reason ; for here neither sar- 



