4 BULLETIN 161, UNITED STATES NATIONAL MUSEUM 



peripheral angle, usually with the ventral slit characteristic of Robulus 

 very distinctly developed. Diameter, up to 1 mm; thickness, 0.4 mm. 



This is a fairly common species in the South Pacific material, 

 especially at those stations occupied by the Albatross from deeper 

 water. Distribution of the various specimens is given in Table 2. 

 There is a considerable degree of variation in the closeness of coiling 

 of the test and also in the number of chambers, as well as in the rela- 

 tive development of the peripheral keel. 



In addition to the stations given in the table, there are small, 

 rather poorly developed specimens referred to this species from near 

 Nairai, Fiji. 



ROBULUS LARVUS (Stache) 



Plate 1, Figure 7 



Cristellana larva Stache, Novara-'Exped., Geol. Theil, vol. 1, p. 232, pi. 23, 

 figs. 11 a, b, 1864. 



Test much compressed, slightly evolute, peripheral end distinctly 

 keeled and somewhat irregular in outline; chambers distinct, very 

 slightly inflated, usually 8 to 10 in the last-formed coil, of uniform 

 shape and increasing uniformly in size as added; sutures very broadly 

 limbate, strongly curved, slightly if at all depressed; wall smooth, 

 finely perforate; aperture slightly projecting, at the peripheral angle, 

 and the ventral slit usually strongly developed. Length, 0.9 mm; 

 breadth, 0.75 mm; thiclcness, 0.3 mm. 



The specimen figured seems to be very close to the species described 

 and figured by Stache from the Tertiary of New Zealand. So far as 

 the present material is concerned, this seems to be a rare species 

 occurring only at Albatross Station H3905, northwest point of Hao 

 Atoll, one-half mile SE., in 425 fathoms. 



ROBULUS COLORATUS (Stache) 



Plate 1, Figure 8 



Cristellaria colorata Stache, Novara-'Exped., Geol. Theil, vol. 1, p. 229, pi. 23, 

 figs. 9 a, b, 1864. 



Test strongly biconvex in peripheral view, in side view close coiled, 

 completely involute, with 6 or 8 chambers in the last-formed coil, 

 periphery strongly keeled; chambers of rather uniform shape, but 

 increasing rather rapidly in size as added, generally of a triangular 

 form; sutures distinct, limbate, distinctly curved; wall smooth, finely 

 perforate; aperture at the peripheral angle, rather definitely project- 

 ing, and the ventral opening usually distinct. Diameter, 1.1 mm; 

 thickness, 0.5 mm. 



This species, like the preceding described by Stache from the Ter- 

 tiary of New Zealand, seems to be rare as a Recent form in the South 



