1869.] 



two gigantic Types of Foraminifera. 



401 



been fully borne out, on the one hand by the discovery of several most 

 remarkable new forms at present existing at great depths in the Ocean, 

 which has been made by the dredgings of M. Sars, Jun., and those of the 

 f Lightning ' Expedition, and on the other by the determination of the 

 real characters of two fossils, one of the Cretaceous, and the other probably 

 of the earlier Tertiary period, which prove to be gigantic examples of the 

 same type. 



The first of these, discovered by Prof. Morris more than twenty years 

 ago in the Upper Greensand near Cambridge, was long supposed to be a 

 Sponge ; but his more recent discovery of two specimens which had been 

 but little changed by fossilization, led him to suspect their Foraminiferal 

 character ; and this suspicion has been fully confirmed by the careful ex- 

 amination made of their structure by Dr. Carpenter, to whom he committed 

 the inquiry, and by whom, with his concurrence, the name Parkeria was 

 assigned to the genus. The second, which was obtained by the late Mr. 

 W. K. Loftus from "a hard rock of blue marly limestone" between the 

 N.E. corner of the Persian Gulf and Ispahan, bears so strong a resem- 

 blance in its general form and mode of increase to the genus Alveolina, that 

 its Foraminiferal character was from the first recognized by the discoverer ; 

 but as all the specimens brought by Mr. Loftus had undergone considerable 

 alteration by fossilization, their minute structure, though carefully studied 

 by means of transparent sections, could not in the first instance be satisfac- 

 torily made out. When, however, Dr. Carpenter's investigation of Parkeria, 

 with the full advantage of specimens but little changed by fossilization, 

 revealed the very remarkable plan of its structure, the investigation of this 

 type was resumed by Mr. Brady (who assigned to it the name Loftusia), 

 with the new light thence derived : for as transparent sections of infiltrated 

 Parkerice furnish a middle term of comparison between specimens of the 

 same type which retain their original character, and transparent sections 

 of infiltrated Loftusice, the last-mentioned can now be interpreted by 

 reference to the preceding ; so that the obscurities which previously hung 

 over their minute structure have been almost entirely dissipated. — The de- 

 scription of the structure of Parkeria in this Memoir is by Dr. Carpenter, 

 and that of the structure of Loftusia by Mr. H. B. Brady; but each has 

 gone over the work of the other, and can testify to its correctness. 



The specimens of Parkeria which have been collected by Prof. Morris* 

 are spheres varying in diameter from about 3-4ths of an inch to about \\ 



* Since this Memoir was completed, the Author has learned that Mr. Harry Seeley, of 

 Cambridge, has collected several specimens of this type, and has been studying it inde- 

 pendently with a view to publication. And Mr. Henry Woodward has placed in his 

 hands a specimen from the Upper Greensand in the Isle of Wight, which is not less than 

 2£ inches in diameter. It is interesting to remark that the " nucleus " of a smaller 

 specimen from the same locality consists of a considerable number of chambers arranged 

 in a spire, the structure of its concentric spherical layers being exactly the same as in the 

 specimens described in the text. 



