20 
CRETACEOUS CTLIOPODA 
It appears to be merely an exceptional case when tlie colony remains permanently 
attached to a foreign body. 
This family must be based npon the growth of the colony, or else it could 
not exist at all. In the present case, however, that the manner of growth can be 
used as a principal divisional character is due to the fact that it is independent 
of the form or structure of the foreign subject to which tlic first cell attaches 
itself, and that, therefore, the colony may be considered as a free-growing one. If 
this circumstance were not considered important enough, the genera woidd have to 
be distributed into other families, as has been done by d’Orbigny. 
The genera belonging to the family are — 
1. Liumlites, Lamx. 
Cells depressed, widely open in front, vibracular cells in more or less complete 
radial series alternating with the regular cells. Colonies free, orbicular, obtusely 
conoid or cupuliform. 
This is the only genus representing the family by a single species in the South 
Indiair cretaceous deposits. 
Whether Pavoliinnlites of d’Orbigny shoidd be regarded as an abnoi’mal 
form of tbis family, or of the Celluforid^:, I am not prepared to say, as I never 
had an opportunity of examining any of the sj)ecies belonging to it; but I believe 
that d’Orbiguy’s Peptolnnulites is nothing else but a Picopora, and that it must 
be referred to the MEMBitASiFORiNjE. 
OUgostresium, Gabb and Ilorn, (Journ. Acad. X. S., Phil., 2nd ser., v, p. 139,) 
only differs from LumiUtes by having the vibracular cells not equally numerous 
as the ordinary cells, but scattered and fewer in number. Tbis, however, also 
occurs sometimes in species of LunuUtes (for instance, L. Uagenoid, Bosq.), the 
vibracula being regular on one side of the colony and fewer and scattered on the 
other. Eor this reason it seems to me very doubtful that OUgostresium will prove 
sufficiently distinct from I/imnlites. 
2. Ueteractis, G. and Horn, (ibidem p. 156). Colony, form of cells, and posi- 
tion of vibracula exactly as in Lximdiles, but the cells do not radiate from the 
centre ; moreover, they arc arranged in straight scries, branching off from a line of 
larger cells, passing diametrically through the centre of the colony from one end to 
the other. 
3. Selenaria, Busk, has discoporid cells with a few others interspersed, of 
soniewhat different shape and structure, provided Avith vibracular openings in jdace of 
the ordinary aperture. 
4. Stichopora, IlagenoAV, forms suborbicular colonies, with dejAressed, anteriorly 
widely open cells, exactly as in LumiUtes, but Avithout any special vibracular cells. 
The species referred by d’Orbigny in his Pal. fran 9 aise, vol. iv, to LunuUtes 
belong to Stichopora ; and I am by no means certain that d’Orbigny’s Liscojlus- 
trellaria, differs from it, unless it be on account of the perfectly flustrinc form of the 
cells, being entirely open in front, Avhile in Stichopora they arc discoporid, being 
( 54 ) 
