dredged up from the Gulf of Manaar. 449 



naked Foraminifer, to whose conjectured existence I have 

 before alluded ; but lest it might be thought that it is merely 

 the chitine without the calcareous material which characterizes 

 this genus, it should be mentioned that, if a specimen of 

 Ceratestina and an ordinary calcareous test of a Foraminifer to- 

 gether be exposed to the influence of an acid solution {ex. gr. 

 dilute nitric acid), the latter will be dissolved and leave 

 scarcely any residue, while the former remains unaffected, 

 proving that the horny substance of the Ceratestina is some- 

 thing more than the chitine which may support the calca- 

 reous material ; indeed the best way of extricating a Cera- 

 testina is to put the calcareous substance containing the 

 specimen into a strong solution of nitric acid, which, all know, 

 is instant destruction to a calcareous test. This kind of Fora- 

 minifer, besides occurring in the cavities excavated by litho- 

 domous sponges in the Melobesian nodules of the Gulf of 

 Manaar, is often observed on the surface of old coral. In some 

 cases the foraminiferal test is composed in one part of the 

 ordinary calcareous material, and in the other of the horny 

 substance only, which condition is so usually seen in one 

 species that it would appear to be rather natural than acci- 

 dental. I allude to a species which I have figured and de- 

 scribed, conjecturally, as the " embryonic form " of Carpen- 

 ieria monticularis ( l Annals,' 1877, vol. xix. p. 213, pi. xiii. 

 fig. 11), but which now, finding it to be a distinct species, I 

 would name " Carpenteria microscopical The chambers of 

 Carpenteria utricularis and also the cells of Polytrema mini- 

 aceuvi are often lined by a stiff horny layer of considerable 

 thickness ; but under what circumstances, I am ignorant, as it 

 does not occur always ; this, however, is secondary and must 

 not be confounded with Ceratestina, in which the horny struc- 

 ture is primary and permanent. 



Ceratestina globular is, n. sp. 

 (PI. XIX. fig. 6, a-g.) 



Test composed of four or more subglobular chambers de- 

 veloped one after another from a primary or embryonic cell, 

 which is subspheroidal and presents the first bud of the 

 stolonic siphon. Composition horny. Colour dark amber 

 (PI. XIX. fig. 6). Chambers increasing in size as they are 

 successively developed upon the stolonic siphon (fig. 6, c) pro- 

 ceeding from the embryonic cell, which is the smallest (tig. 6, a); 

 arranged more or less spirally, fitting upon each other, as they 

 are successively developed, by the convex surface of the pre- 

 ceding being; received into a lunate one of the following: 

 chamber (fig. 6, c), and all tied together on the inner side of 



