REPORT ON THE ACTINIARIA. 39 



The number of mesenteries varied in the three specimens investigated between 

 twenty-eight and thirty-six, according to their size. The dorsal and ventral zones of 

 mesenteries approximate always with macromesenteries. 



No channel filled with cells is present at the bases of the mesenteries ; the muscle- 

 pennons indistinct ; the generative organs so abundantly developed as to fill the 

 greater part of the ccelenteron. These latter occur only on the macromesenteries, 

 and consisted of testicular follicles in the three specimens studied. 



The coenenchyme is extremely thin, and possesses internally smooth connecting- 

 tubes lined by endoderm ; on the upper surface Foraminiferal shells are sparsely 

 embedded ; while on the other side, which covers the Gastropod shell, these are entirely 

 absent. 



The name thalamophUus was chosen with reference to Thalamophora and Poly- 

 thalamia, names which have been applied to the Foraminifera. 



Epizoanthus stellaris* n. sp. (PL I. fig. 4). 



" Polyps of inconsiderable height, nearly saucer-shaped; body-wall vertical at the 

 sides, but strongly flattened above ; on its horizontal upper surface are numerous radial 

 ridges, separated by furrows, 15-20 in the adult animal ; colour of the colony dark 

 greyish-brown ; deposits very various." 



Habitat. — Station 201, off Samboangan, Philippine Islands; 82 fathoms. 



Dimensions. — Of the individual polyps— height, 0'05-0"4 cm. ; diameter, 0'15-0 - 7 cm. 



" Of this species I possess a colony, covering the rooting spicules of a Hyalonema for 

 a distance of about 14 cm., and consisting of about 100 individuals. The coenenchyme 

 forms a tube open at both ends, and surrounds like a sheath the bundle of spicules, the 

 latter being about 5 mm. thick. The individuals spring from it at longer or shorter 

 intervals by an elliptical base, measuring in the largest polyps (3-4 mm. high) about 

 5-7 mm. in diameter. From these to the smallest, which hardly project above the 

 coenenchyme, and are 1-5-3 mm. broad, by 0'5-l mm. high, every transition is found. 

 All the animals are strongly contracted ; on the strongly flattened, discoidal, horizontal 

 surface of the body -wall may be dimly seen the entrance to the interior by a circular 

 pit. From this point outwards radiate over the surface of an adult specimen, about 

 15-20 ridges separated by furrows. 



" The colour of the colony is a dirty dark-grey. The body-wall is of considerable 

 thickness, caused by the strongly developed mesoglcea. The exterior surface of the 

 latter is charged with various deposits, consisting of irregular grains of sand and lime, 

 sponge spicules of very varied origin, and finally of the small dark crystalline bodies 

 which cause the dark tint of the colony. These deposits occur in additional quantity 

 on the radial ridges before mentioned. They are continued inwards as elevated ridges 

 over the edge of the covering fold without a break, and run even further, on the inner 



