80 PROCEEDINGS OF THE NATIONAL MUSEUM. vol.43. 



Genus THESEA Duchassaing and. Michelotti (modified by 



Nutting). 



Calyces verruciform, their walls filled with broad scale-like spindles 

 armed with thorny processes on one side only, the opposite edge being 

 tuberculate. Scales imbricating, the thorny processes being upper- 

 most and overlapping the lower edges of other spicules. Heavy 

 ordinary spindles are also present. 



THESEA PLACODERMA Nutting. 

 Thesea placoderma Nutting, Muriceidse of the Siboga Expedition, 1910, p. 54. 



Colony flabellate, not reticulate, 7.3 cm. in height and with a spread 

 of 4.6 cm. 



The main stem is 2 mm. in diameter and gives off a few stubs of 

 branches on one side and a number of simple twigs and two compound 

 branches on the other. Branches of the third order sometimes pro- 

 duced. The distance between branches varies considerably, perhaps 

 averaging 4 to 6 mm. The calyces are mostly lateral, with a few on 

 front and back, particularly on distal parts. They are ordinarily 

 less than 1 mm. apart. 



The individual calyces are low verrucse of variable height, usually 

 not exceeding 1 mm., and about 1.3 mm. in diameter. Their walls 

 are filled with heavy plates or spindles with their upper edges armed 

 with a row of jagged teeth. These scales are imbricating, the teeth 

 pointing upward and outward and surrounding the margin with an 

 irregular series of points. The polyps are retracted to their collarets. 

 The operculum is heavy, each flap being composed mainly of two long 

 spindles with their proximal ends divaricated and their distal ends 

 approximated to form a point near the center of the mass of infolded 

 tentacles. 



Spicules: These are of the characteristic Thesea type, as described 

 above. The coenenchyma of stem and branches is covered with scale- 

 like plates with irregular, often jagged, edges. 



Color: The axis is dark brown, and the general color of the colony 

 is grayish-brown. 



Localities.— ^tOition 4894; Ose Saki Light, N. 41° E., 5 miles; 95 

 fathoms. Station 4936; Sata Misaki Light, N. 21° E., 5.7 miles; 103 

 fathoms. 



The type-locality is in Flores Sea, East Indies, 73 meters. 



Genus ACIS Duchassaing and Michelotti (modified by 



Nutting). 



Colony branched, calyces varying in form, their walls and the ten- 

 tacle bases with spindles not en chevron. Spicules of the coenenchyma 

 very heavy spindles or plates, their edges often fitted as in mosaic. 



