REPORT ON THE AGTINIARIA. 13 



Anthozoa, the development of radial (mesenterial) folds which commences in the 

 former being further advanced in the latter. In this case the ectodermal longitudinal 

 musculature of Corynactis and the Cerianthi would be, as it were, heirlooms from the 

 Scyphostoma?. Both genera would thus retain an ancestral character no longer to be 

 found elsewhere among Anthozoa, with which would agree that both genera must on 

 other grounds be placed near to the original ancestor of the group. Of all Hexactinise, 

 the Corallirnorphidse are, next to the Halcampce,, the most primitive ; the Cerianthidse, 

 again, must be derived from the extremely primitive Edwardsise. 



Family 2, Antheomorphid^e, Hertwig. 



Genus Ilyanthopsis, n. gen. 



Antheoinorphidse with the tentacles in several rows ; body-wall smooth ; body 

 goblet-shaped, broadening upwards from the small pedal disc to the broad oral disc. 



Ilyanthopsis longifilis* n. sp. (PI. II. fig. 2). 



Tentacles very long, pointed, with an obvious terminal pore, ranged in four circlets, 

 increasing in length from the centre outwards. 



Habitat. — Reef of the Bermudas, June 1873. One specimen. 



Dimensions. — Diameter of base, 4 cm., of oral disc, 7 cm. ; height, 3"5 cm. 



The single specimen, which was well preserved but strongly contracted, in its 

 shape occupies a middle position between Aiptasia and Ammonia. The base is 

 relatively small, the body not very high, but broadening out conically towards the 

 mouth. The body-wall being raised in goblet shape over the edge of the oral disc, the 

 animal possesses a "collar" in the sense of Angelo Andres, and consequently, owing 

 to the absence of cinclides and acontia, must be reckoned near the Ilyanthidse. From 

 these it differs in the presence of a well-developed pedal disc, by which it undoubtedly 

 attaches itself to rocks. 



The thin body-wall is smooth, except for transverse wrinkles due to the strong 

 contraction of the mesenteries. No sphincter is present. The circular muscle-lamella 

 is, in all parts of the body-wall equally, pleated into muscular lamina?, which are low, 

 and either not at all or only slightly arborescent. 



The tentacles are very numerous, and are arranged in four rows, the oral disc being 

 free from them in the immediate neighbourhood of the mouth. Since I counted but 

 160, not all the tentacles of the sixth order can as yet have been developed. The 

 longest of them were some 4 cm. in length, and - 5 cm. broad at the base ; the slightly 

 truncated tip possessed a small pore. In studying the ectodermal muscle-lamellag, 

 peculiarities presented themselves which suggested the longitudinal muscles on the 

 outer surface of the body-wall in Cerianthus. The muscular pleats are generally 



