14 TROCIiOCYATHUS. 



finely dentate, slightly sinuous, grcanulated, not exsert, forming six 

 systems of four cycles ; one of the systems sometimes incomplete. 

 Pali thick, with sinuous surfaces, fronting all the septa but those of 

 the fourth cycle ; those of the second largest. Columella thick, 

 formed of a dense mass of papillose processes, arranged in rather 

 indistinct rows coinciding with the pali. 



Height 13 to 19 mm.; diameter 9 mm. 



In 100 to 200 fxthoms off the Florida Reef; less common than the 

 following species. Full-grown specimens rather rare. 



Thecocyathus laevigatus Pourt. 



Plate v., figs. 3 and 4. 



General form, costas, and epitheca not different from preceding 

 species. Septa in four cycles and six incomplete systems, the fourth 

 cycle remaining undeveloped in one of the systems and two half- 

 systems. Septa smooth and as if enamelled, with very fine granules 

 and entire l)order. Pali only before the septa of the third order, and 

 seldom complete. Columella papillose, formed of four to ten pointed 

 and smooth processes. 



Height 9 to 13 mm., diameter 6 mm. 



Rather abundant in 100 to 200 flithoms off the Florida Reef; also 

 found living in 315 fathoms off Double-Headed Shot Ke^^s. 



TROCHOCYATHUS M.-Edw. & H. 



Trochocyathus ? coronatus Pourt. 



Platylrochus coronatus Pourt. Bull. Mus. Comp. Zobl., No. 6. 



Plate VI., fig. 16. 



Corallum free, cylindrical ; horizontal base with a knob in the 

 middle. Primary and secondary costa3 having each a large tuber- 

 cle at the junction of the vertical wall with the base. Calicle cir- 

 cular. Septa in six complete systems and four cycles, meeting in tlie 

 centre. Tertiary septa frequently but not regularly coalescing with 



