246 



BULLP:TIN 100, UNITED STATES NATIONAL MUSEUM. 



Diameter up to 3 mm. 



Distribution. — Typo specimen (U.S.N.M. No. 9136) from Albatross 

 station D5570, in 330 fathoms (604 meters), north of Tawi Tawi, 

 bottom temperature 52.3° F. (11.2° C). It also occurred at D5548, 

 in 232 fathoms (424 meters), off Jolo Island, bottom temperature 

 53.5° F. (11.8° C), and D5579, in 175 fathoms (320 meters), off 

 Darrel Bay, Borneo, bottom temperature 55.3° F. (12.9° C). 



This is one of the most beautifully sculptured species found in the 

 Philippine region. 



Cristellaria tumido-costata — Material examined. 



CRISTELLARIA TUMIDO-COSTATA, var. LABYRINTHICA Cushnian. 



Plate 50, figs. 1 a, b. 



Cristellaria tumido-costata, var. labyrinthica Cushman, Proc. U. S. Nat. Mus., 

 vol. 51, 1917, p. 660. 



Description. — Variety differing from the typical in the shape, which 

 is more tumid, the periphery more broadly rounded than in the typ- 

 ical, and the ornamentation, which consists of a peripheral series of 

 costae, as in the typical; but the costae above the sutures obsolescent 

 and the intermediary costae becoming the prominent sculpture, and 

 becoming shorter, irregular, making a labyrinth-like network of 

 raised ridges. 



Distribution. — The variety was found only at Albatross station 

 D5567 in 268 fathoms (491 meters), north of Tawi Tawi, bottom tem- 

 perature 52.° F. (11.1° C). Type (U.S.N.M. No. 9137). 



Several specimens from this station show the relation between this 

 variety and the typical form. 



Cristellaria tumido-costata, var. labyrinthica — Material examined. 



