214 Mr. H. J. Carter on Foraminifera 



ceived between tlicm ; while a young specimen of the latter 

 variety presented a distinet helical commencement from a pri- 

 mary or embryonal chamber, afterwards becoming lost in the 

 acervuline group around it (fig. 14), like one kindly sent to me 

 for examination by Dr. Carpenter ; also a cinnamon variety 

 presents a distinct embryonal cell, followed by an irregular he- 

 lical development, finally surrounded by circles of chambers 

 with straight radiating partitions (fig. 15), such as I have before 

 figured in Polytrema mimaceum (Ann. & Mag. Nat. Hist. 1876, 

 vol. xvii. pi. xiii. fig. 2), where the confused centre is also no 

 doubt an irregular development of the helix. So that they all 

 probably commence in this way; and Avhere the colour does not 

 assist, the irregular form of the chambers (fig. 14, h), together 

 with the smaller size of the tubulation, may serve to distinguish 

 the embryonic forms from those of Planorhalina. 



In my paper on the Polytremata (Ann. & Mag. Nat. Hist. 

 t. c. p. 206) I have stated that I possess several specimens of 

 Australian Orbi'toHtes, " in which the chambers are charged 

 with embryos ; the latter are all ellijytical elongate." The 

 '^elliptical" form, I must say, always staggered me; but I now 

 find that the largest of them present a line running through the 

 long axis — which, together with the presence here and there of 

 other minute Diatomaceee, seems to indicate that they are all the 

 frustules of a Cocconeis. The parasitic habit of this species is 

 well known ; and it is not improbable that in a still more minute 

 form (for they only avea-age l-1800th inch in their longest di- 

 ameter, with two to six in almost every chamber) they may 

 have got into their present position through the stoloniferous 

 apertures on the margin of the Orhitolites. 



Planorlulina larvata (Parker and Jones, Phil. Trans. 1865, 

 ])1. xix. figs. 3, a, h). 

 The specimen of Tiihlpora musica also bore specimens of 

 Planorhulina larvata^ in a young one of which there is a di- 

 stinct helical development from a primary embryonic chamber, 

 aftei-wards followed by the usual forms (fig. 16); and in another 

 instance a discoid regularly formed Foraminifer was found 

 outside three distinct cells of Planorhulina vulgaris with their 

 peculiar apertures (fig. 17, hbb,cc), which had been developed 

 ifrom the last of the helical chambers (fig. 17, a). To the 

 former I have before alluded, as well as to the helical develop- 

 ment, at first, o^ Pulytremaminiaceum ; and from them we learn 

 that, however dissimilar the ultimate form of a Foraminifer may 

 be, they all commence in the same way, viz. from a primary 

 chamber or embryonic cell followed for a short distance by 

 a helical development. Thus, like all other organized bodies, 



