182 Mr. H. B. Brady on Saccammina Carteri, 



segments and the comparative tenuity of the inteiTnediate 

 processes woukl be sufficient to account for the separation into 

 single chambers, were this less constant than it is ; but there is 

 no need to suppose that the single segment may not represent a 

 perfect animal equally with the many-chambered shell. Oc- 

 casionally, though very rarely, a chamber is found with a round 

 imperforate base and a single orifice at its ajDcx ; and if this 

 is taken to correspond to the ordinary form of Lageyia, the 

 fusiform chambers may be regarded as analogous to the disto- 

 mous varieties of that genus. The moniliform fossils might 

 be compared to the Ahdosarue, but that all that have as yet 

 been met with have an apeiinre at each end of the series of 

 segments, and, for any thing known to the contrary, the test 

 might extend itself indefinitely in either direction. 



The test is composite and arenaceous, the constituent parti- 

 cles being fitted and cemented together so as to give a nearly 

 smooth exterior. The size of the sand-grains and their mode 

 of aggregaticm is a character of some importance amongst the 

 recent Lituolida ; but, as has been before stated, the process of 

 mineralization has obscured the minute structure of the fossil 

 in these particulars. 



The interior of the test is commonly smooth, resembling 

 the recent Saccammina ; but it sometimes presents a sm*face 

 of very short, delicate, labyrinthic, shelly ingi'owths, as shown 

 in PL XII. figs. 3 & 4. This cancellated or labyrinthic struc- 

 ture is often met Avith amongst the arenaceous Foraminifera, 

 and in some genera it is developed to an enormous extent. 



Here and there a specimen may be found with a sort of 

 circular patch on the sm'face, which has the appearance of a 

 cicatrix resulting either from the gradual closing-in of an 

 orifice or possibly the reparation of some injmy to the shell- 

 Avall. These slightly raised concentiic markings, apparently 

 deposited regularly from without inwards, occumng frequently 

 and with considerable uniformity, can scarcely be accidental. 

 The positions in which they are generally noticed, viz. the 

 sides rather than the ends of the segments, is an objection, 

 though possibly not a fatal one, to the supposition that they 

 mark the closure of normal apertm'es. 



When first investigated, the characters of the fossil seemed 

 sufficiently distinct from those of any kno-\\Ti type of Foramini- 

 fera to necessitate the establishment of a new genus for its 

 reception, and the generic term Carteria* was provisionally 



* See Brit. Assoc. Reports, 18G9 (Exeter Meeting), p. 381. I hoped 

 to a-ssociafe the type with the name of my friend II. J. Carter, F.R.S., 

 who has laboured ."^o assiduously and successfully amongst the Protozoa. 

 A.s the matter stands, the specific term only is left at my disposal 



