CARPENTER ON FORAMIN IFER4 . 195 



tions of the sarcode body. Hence it is readily conceivable how a canal- 

 system may be formed with considerable regularity in an organism in 

 which the intermediate skeleton attains a considerable development, 

 whilst it may be wholly or partially deficient in another, in which that 

 supplemental deposit of calcareous matter has taken place to a much 

 smaller extent. And it is to be specially observed that all those forms 

 in which it is at present known to attain its greatest completeness, are 

 those tropical or semi-tropical types, in which the influence of warmth, 

 abundance of food, and other external agencies in promoting develop- 

 ment, appear specially to favour the largest growth and the most special- 

 ized evolution of the Foraminiferous type. 



The relations of the forms belonging to the family Miliolitidce have 

 recently been investigated by Mr. W. K. Parker ;* and his results are in 

 perfect accordance with my own. Thus in each of the genera Cornuspira, 

 Hauerina, and Vertebral 'ma, Mr. Parker reduces all the reputed species 

 to one ; while he shows that even their generic differences are really but 

 of small account. And he not only in like manner reduces all the 

 reputed species of the genus MMola to the level of varieties, but brings 

 down to the same rank the reputed genera Spirdloculina, Biloculina, 

 Triloculina, and Quinqueloculina ; the differences between which, arising 

 from asymmetrical growth, and from variations in the form and num- 

 ber of the chambers, cannot be regarded as even of specific value, the 

 Milioline plan of construction being preserved throughout. In the large 

 group of N'odosarina which has been carefully studied by Messrs. T. 

 Eupert Jones and "W. K. Parker, f those gentlemen have felt themselves 

 justified, on the like grounds in reducing a multitude of reputed genera 

 and species to a single type. Between the nautiloid Cristellarice and the 

 straight moniliform or rod- like Nodosarice, which agree in essential 

 characters of structure and mode of growth, they find such a continuous 

 series of connecting links, that no line of demarcation can be anywhere 

 drawn, the straight, the curved, and the spiral forms passing grada- 

 tionally one towards another ; and the extreme forms being thus brought 

 together, the various intermediate grades which have been distinguished 

 by systematists under the generic names Glandulina, Lingulina, Den- 

 talma, Rimulina, Yaginulina, Planularia, Marginulina, Dimorphina, 

 Flabellina, and Frondicularia, necessarily fall into the same category. 



The same general doctrine having thus been shown to hold good in 

 regard to all the chief natural subdivisions of the Foraminiferous group, 

 it is not my. purpose at present to prolong the inquiry in this direction. 

 The systematic study of this tribe needs to be prosecuted far more ex- 

 tensively than my own time and opportunities have admitted, to enable 

 even an outline scheme to be framed, which should represent an 

 approach to the true relations of its principal families. But I think I 



* Transactions of the Microscopical Society for 1858 (New Series, vol. vi.), p. 53. 

 f Annals of Natural History, Nov., 1859" p. 477 ; and Quarterly Journal of the Geo- 

 logical Society, August, 1860, p. 30'2 and November, 1860, p 454. 



