dredged up from the Gulf of Manaar . 453 



be restricted to those only whose size renders them most con- 

 spicuous, none of which sensibly exceed an eighth of an inch 

 in diameter ; and these belong to D'Orbigny's genus Amplii- 

 stegina, for a more intimate acquaintance with which I must 

 refer the reader to Profs. Parker and Jones's account [apud 

 Carpenter, ' Introduction,' p. 242). 



Amphistegina, D'Orbigny. 



On the borders of the Indian Ocean there are several species 

 of these nummuline forms ; and although they may vary 

 slightly in their structural features here and there, for some of 

 the " borders " are very wide apart (ex. gr. the Gulf of Aden 

 and the south-west corner of Australia), still the genus extends 

 to all of them ; and therefore the Gulf of Manaar is not with- 

 out its representatives, among which is the well-known A. 

 mammillata of D'Orbigny. There is also another compressed 

 globose form, unless it be the thick part of a Heterostegina 

 worn down to this, with the same kind of structure as Hetero- 

 stegina, and a third, which is the largest of all, wherein the 

 chambers are extremely numerous and regular, closely approxi- 

 mated, awl-shaped, and much recurved, with a thick nummuline 

 marginal cord between the whorls. 



Calcarina calcar, var. Mspida, n. var. 



The same remarks respecting the varietal differences apply 

 to Calcarina calcar, which is found in the Red Sea, at the Mau- 

 ritius, and, under the form of Trioporus baculatus, in Poly- 

 nesia, while it is also abundant in the Gulf of Manaar, but 

 here under the hispid form mentioned. This hispid state 

 bears the same relation to Calcarina calcar as the hispid 

 form of Calcarina Spengleri bears to the latter species in Poly- 

 nesia, well shown in Dr. Carpenter's representation (' Intro- 

 duction,' pi. xiv. fig. 6). All, not averaging more than 

 l-24th inch in diameter, are much smaller than C. Spengleri, 

 while it is not unusual to find the hispid form of the latter, 

 like that of the former, sunk into the flat surface of an 

 articulation of Flabellaria opuntia side by side with Gypsina 

 vesicularis. 



Alveolina sinuosa, n. sp. seu var. 



The genus Alveolina also occurs on the borders of the 

 Indian Ocean generally ; but whether that from the south- 

 west coast of Australia has been named or not I cannot say. 

 Suffice it to state, then, that if so, A. sinuosa must be considered 

 a variety ; for I can see very little difference between it and 

 that which occurs on the coast of Australia, as well as the 



Ann. & Mag. N. Hist. Ser. 5. Vol. v. 31 



