176 SPOLIA ZEYLANICA. 



This species has from eighteen to twenty tentacles and five 

 small anal teeth. Opposite each tooth is a group of papillae. 



The ambulacral appendages all have well-developed sucking 

 discs, but it is highly probable that the ventral appendages 

 alone are used in locomotion. 



Internal Structure. — The calcareous ring is well developed. 

 The radial pieces have three anterior indentations alternating 

 with four blunt processes. The inter-radials possess a single 

 anterior tooth. The posterior part of each radial piece is 

 separated from the anterior part by a well-defined ciu'ved 

 suture. 



There is generally one stone canal attached to the right side 

 of the dorsal mesentery and one large Polian vesicle. 



Spicules. — The calcareous deposits consist of tables and 

 peculiar hollow fenestrated bodies. The tables are compara- 

 tively scarce, and are masked to a great extent by the large 

 numbers of fenestrated bodies that lie in the deeper layers of 

 the perisome. The tables are 60 ^ in diameter and 50 jj, high. 

 The hollow spicules are 80 ^ long. 



Remarks. — According to Selenka the only difference 

 between this species and Argiodia hadra (Selenka) is in the 

 nature of the calcareous ring. In the latter form the antero- 

 posterior axis of the radials and inter-radials is much longer 

 in proportion than in Argiodia maculata. I am inclined to 

 think that Argiodia hadra, apparently described by Selenka 

 from a single specimen, should be included in the species 

 maculata. 



General Distribution. — Indo-Pacific region. 



Argiodia flavo-castanba (Theel). 

 (PI. XXVIII., fig. 3.) 



MjXlleria fMvo-castanea, Theel 1886 (26). 



One specimen from Munich, found in the Red Sea. 



External Characters. — The specimen under examination is 

 much larger than Theel's specimen and is different in colour, 

 but otherwise agrees with Theel's description. It is 280 mm. 



