84 BULLETIN 11, UNITED STATES NATIONAL MUSEUM. 



The very early stages in Nevillina are not described, but there is 

 evidently an early triloculine stage followed by a biloculine one before 

 the adult embracing chamber is formed. These stages are shown in 

 Sidebottom's figures and noted by him. Microspheric specimens 

 would undoubtedly show the complete series of developmental stages 

 already noted for Idalina. 



This is, then, a most interesting recent genus, allied closely with 

 these upper cretaceous genera of southwestern Europe. It is found 

 also in that portion of the oceans which is known to contain some of 

 the most ancient forms in regard to certain groups of the mollusca at 

 least. 



A single species is known and it seems to be very rare. 



NEVILLINA CORONATA (Millett). 



Plate 35, figs. 2-5. 



Biloculina coronata Millett, Journ. Roy. Micr. Soc, 1898, p. 263, pi. 6, figs. Ga-c. 

 Nevillina coronata Sidebottom, Mem. and Proc. Manchester Lit. and Philos. 

 Soc, vol. 49, pt. 2, No. 11, 1905, p. 1, pi., figs. 1-8. 



Description. — "Test elongate, more or less pyriform, circular in 

 transverse section. Aperture circular, complex, formed by numerous 

 incurved lamellae, meeting centrally." 



Length, up to 2 mm. 



Distribution. — Millett's specimen was from the northeast coast of 

 Sumatra, while those of Sidebottom were from Port Blair, east side of 

 Andaman Island, at entrance to the port, between Ross Island and 

 the main island, 16 fathoms, and Sulu roadstead, 12 fathoms. The 

 last station is followed by this note: "Very strong tide sweeping 

 through the anchorage. Many shoals, and reefs of growing coral in 

 the Sulu Sea, and many banks frequented by pearl fishers." 



From the fact that the species does not seem to have been taken by 

 the Cliallenger and that Millett had but a single specimen it is evident 

 that it is a very rare species. 



The description and figures are from Sidebottom. 



Genus PENEROPLIS Montfort. 



Nautilxis (part) ForskAl, Descr. Anim., 1775, p. 125. 



Peneroplis Montfort, Conch. Syst., 1808, 65th genre, p. 259. — II. B. Brady, 

 Rep. Voy. Challenger, Zoology, vol. 9, 1884, p. 203. 



Description. — Test planospiral, at least in the early stages, whole 

 test lenticular, thick or much compressed, circular, crosier-shaped or 

 cylindrical; surface smooth or the chambers longitudinally striate; 

 chambers entire, not subdivided as in the following genera; aperture 

 in the complanate forms consisting of a linear series of pores on the 

 apertural face, in the less compressed forms an irregularly arranged 

 series of pores and in the more or less uncoiled forms often becoming 

 dendritic. 



