REPORT ON THE ACTINIARIA. 101 



are of so little importance in the constitution of the body of the Actinia that their 

 appearance has not even been followed by an increase in the number of the tentacles. 



Family, Polyopid^, Hertwig. 



Paractiniae, without pedal disk, posterior end of the body round and saccular, with 

 aboral opening (?) ; tentacles transformed into stomidia by retrograde metamorphosis. 



In earher systems the Polyopidse would have been placed among the Ilyanthidse, to 

 which family, apart from the absence of tentacles, they bear a strong external resemblance. 

 It is quite possible that at some future time forms may be found which shall furnish a 

 closer link between our PolyopidaB and the Edwardsise formerly described as Ilyanthidse ; 

 more especially as the Edwardsise occupy in some measure a central position in the midst 

 of the Actiniae, and send out lines of affinity in various directions. At present, however, 

 it is more convenient to separate the Edwardsise and the Polyopidse as the paired 

 grouping of the septa, which is so pronounced in the latter, is still wanting in the former. 



Polyopis, n. gen. 



Polyopidae with smooth wall, the surface having longitudinal furrows indicating the 

 position of the septa ; circular muscle wanting. 



Polyopis striata (PI. II. fig. 11 ; PI. XL figs. 1-12). 



Wall with thirty-six longitudinal lines ; oral disk with thirty-six strongly developed 

 radial swellings and thirty-six marginal stomidia arranged in a circle. 



Habitat.— ^t&i\o\i 299. December 14, 1875. Lat. 33° 31' S., long. 74° 43' W. 

 Depth, 2160 fathoms. One specimen. 



Dimensions. — Height, nearly 2 cm. ; breadth, 2 cm. 



Colour. — (Determined from the spii-it specimen) wall saffron-yellow, oral disk whitish, 

 oesophagus dark brown. 



The small Actinia without tentacles, which I call Polyopis striata (677-;^ = opening), 

 was probably sac-shaped during life ; its rounded posterior end probably stuck in the 

 sand, whilst its broad anterior end formed by the oral disk projected freely. In conse- 

 quence of packing, the animal was pressed quite flat, the oral disk and oesophagus turned 

 out and very much injured, the septa consequently misplaced and torn. The difficulty of 

 examining the septa was increased by the fact that from the hardening by alcohol, the 

 septa had stuck together, and could not be easily separated by dissection. The 

 preservation of the tissue was satisfactory, especially that of the epithefium on the oral 

 disk, oesophagus, and septa. 



The wall is of a delicate yellowish colour, which is contained in the endoderm, as the 

 ectoderm is rubbed off and the mesoderm colourless and transparent after the epithelium 



