TROPICAL PACIFIC FORAMINIFERA OF ALBATROSS 61 



Test longer than broad, triloculine, typically with the chambers 

 with a truncate periphery, the angles somewhat extended; cham- 

 bers distinct; sutures somewhat depressed; surface ornamented by 

 reticulations both on the sides and on the outer angles; aperture 

 elongate, with a definite thin lip, slightly everted, tooth elongate, 

 narrow, extending above the outline of the aperture. Length, 

 0.8-1 mm.; breadth, 0.7-0.9 mm; thickness, 0.55-0.6 mm. 



The reticulately ornamented species have been noted under many 

 different names since the earliest ones given by d'Orbigny. D'Or- 

 bigny's Triloculina reticulata was not figured in the 1826 paper, and 

 while it may apply to various forms with a rounded periphery 

 such as those to which Brady assigned the name in the Challenger 

 report, our specimens with definitely angled chambers are much 

 closer to the West Indian species described by d'Orbigny in 1839 

 as Triloculina oicarinata. 



Our specimens are all from Mokaujar Anchorage, Fiji, where this 

 form is very abundant, but it was not found in any of the other 

 stations. There is as usual a considerable degree of variation in 

 size and arrangement of the reticulations, and in these Fiji speci- 

 mens the peripheral face of the chambers is highly ornamented, 

 while the sides are much less so. 



TRILOCULINA sp. (?) 



Plate 13, Figures 7 a~c 



There are in the collections certain forms similar to that here 

 figured that are very difficult to place specifically. The species seems 

 to be on the border line between Triloculina and Quinqueloculina, 

 and it is figured here in order that attention may be called to this 

 peculiar form. 



Genus PYRGO Defrance, 1824 



Pyrgo Defrance, Diet. Sci. Nat., vol. 32, p. 273, 1824. — Cushman, Cushnian 

 Lab. Foram. Res. Special Publ. No. 1, p. 155, 1928; U. S. Nat. Mus. Bull. 

 104, pt. 6, p. 67, 1929. 



Miliola (part) Lamarck, Ann. Mus. d'Hist. Nat., vol. 5, p. 351, 1804. 



BilocuUna d'Orbigny, Ann. Sci. Nat., vol. 7, p. 297, 1826 (genotype, by desig- 

 nation, B. bulloides d'Orbigny). 



Genoholotype. — Pyrgo laevis Defrance. 



In its microspheric form this genus shows all three stages — quin- 

 queloculine, triloculine, and biloculine — but in the specimens with 

 a small megalospheric proloculum acceleration takes place and the 

 quinqueloculine stage is skipped, and in specimens with a very 

 large proloculum the biloculine character is taken on at once and 

 both the quinqueloculine and triloculine stages are skipped entirely. 



