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specimens are so infiltrated with mineral matter that the internal 

 structure is obscured. Nevertheless enough is seen to make 

 their relationships tolerably certain. 



We originally obtained the names of Orbitoides ma7itelii and 

 the other varieties found in Trinidad, &c, and recorded . in my 

 Paper in the Geological Society's Journal, and elsewhere, from 

 T. Rupert Jones, who published a Paper on the Orbitoides from 

 Jamaica in the same Journal in 1863, page 514, and again in the 

 Geological Magazine, 1864, page 103. It was from this last 

 rather than the first-named Paper that we got the names above- 

 mentioned, for in my Paper of 1863, read to the Scientific Asso- 

 ciation, and re-published in the "Geologist," 1864, page 159, I 

 did not venture to use specific names. Speaking of the Antiguan 

 Orbitoides, Rupert Jones says : "This large thin Orbitoides is of 

 considerable interest ; it belongs to that species of Orbitoides 

 which is characterized by having vertical partitions to its central 

 layer of chambers, and these more or less cylindrical, namely, O. 

 mantelii. It is the exact counterpart of the Orbitoides I have 

 lately observed in the limestone from Malta." He further states 

 that he found the same variety of O. mantelii in the Jamaican 

 limestone mixed with 0. dispansa and O. fo? r tisii. Dall, (Proc. 

 U. S. N. Museum 1896, page 329) observes that in no case which 

 he has examined has the West Indian species proved to be the 

 true O. mantelii. Upon this Hill remarks (Geology of Jamaica, 

 page 144) : "It is now apparent that Dall's recent statement * * * 

 to the effect that Orbitoides mantelii has not been found in the 

 West Indian species is incorrect, and we must accept the occur- 

 rence of this species as identified by the eminent authorities T. 

 Rupert Jones and R. M. Bagg." The variation in Orbitoides 

 leads me to believe that the different forms found in the Trinidad 

 and other West Indian rocks are all really of one species. I can- 

 not see any true and constant differences between our fossils and 

 those figured by Brady and Silvestri in the places quoted, and by 

 Carpenter (Introd. PI. XX). In these circumstances I do not 

 feel competent to make any change in the nomenclature, and to 

 avoid confusion I leave matters in this respect as they were be- 



