178 SPOLIA ZEYLANICA. 



40 mm., and several of them are only 25 mm. Thus, this 

 species is very different from other species of the genus, the 

 members of which are usually characterized by a large size. 

 The small size of the specimens makes it difficult to determine 

 the characters. The colour is generally dark brown, but the 

 Seychelles specimen is light yellow. The ventral pedicels 

 are crowded and are of comparatively large size. The dorsal 

 papillse are apparently much smaller and less numerous. There 

 are twenty tentacles, and the anus is surrounded by five 

 minute teeth. 



Internal Structure. — The calcareous ring agrees with 

 Fisher's figure more than with Selenka's. The two anterior 

 lateral notches of the radial pieces figured by Selenka are not 

 present in any of the specimens I have examined. The small 

 size of the specimens has not permitted the stone canal and 

 Polian vesicles to be clearly made out. Selenka describes 

 one of each, and Fisher makes out two Polian vesicles and 

 one stone canal. Cuvierian organs are present, according 

 to Fisher. 



Spicules. — These consist of tables and smooth buttons, and 

 closely resemble the deposits of Halodeima difficilis, and prob 

 ably explain why Haacke (according to Ludwig) mistook some 

 specimens of the latter species for the species under discussion. 

 The tables are pierced with about eight peripheral holes, 

 which alternate with an equal number of smaller holes. The 

 base is 70 ^ in diameter, and the tower, which bears a spinous 

 top, is about 55 jji, in height. The buttons are oval and smooth, 

 and are irregularly pierced by about three pairs of holes. 

 These buttons are about 85 ^ in length. 



Remarks. — This species is distinguished from Argiodia 

 flavo-castanea by (a) its size ; (6) the shape of the calcareous 

 ring, although this character is apparently variable ; and (c) 

 the nature of the buttons. So far as our small knowledge of 

 the two forms goes, there is no reason to believe they are 

 identical, as Theel and Bedford have suggested. 



General Distribution. — The distribution of this species is 

 interesting, and includes Florida, Seychelles, Maldives, 

 Hawaii, and Funafuti. 



