526 EUITH M. PRATT. 



The autozooids are slightly larger than those of many species. The anthocodial portion 

 in the preserved state is very short, being only about -Q mm. in length, so that the crown 

 with its eight radiating tentacles appears to be apposed to the surface of the capitulum. 

 The average diameter of a fully expanded crown is 1"5 mm. Below the surface the diameter 

 of an autozooid gi-adually diminishes posteriorly. 



The tentacles are long compared with those of other species, and are about "7 mm. in 

 length when extended. They are blunt at the tip and are almost of uniform breadth. 

 When carefully examined microscopically a double row of rudimentary pinnules may be seen 

 down each side (fig. 27). In this respect this form resembles Sc. capitale and approaches Xenia. 



The stoniodaeum is long and convoluted, and the siphonoglyph is provided with long 

 cilia. The mesenteries are larger and stouter in this form than in any other species in the 

 collection. The dorsal mesenteries have large and broad, grooved mesenterial filaments, and 

 the ventral and lateral mesenteries have longer and broader filaments than those of other 

 species. The coelenteric cavities of neighbouring autozooids are often connected by means 

 of short transverse vessels as in Sarcophytum (fig. 3). I have been unable to find male 

 or female cells in the specimen of this species. 



Sipbonozooids are present but are clearly degenerate in this species, being represented 

 by minute caeca from the large transverse vessels of the superficial canal system. They are 

 regularly distributed in the peripheral portions of the capitulum between the autozooids. They 

 apparently have no aperture to the exterior and therefore cannot be functional as true 

 sipbonozooids. In decalcified stained slips of tissue from the surface of the colony the caeca 

 may be clearly seen in surface view through the ectodermal tissues, and average "07 mm. in 

 diameter. There is Uttle doubt that the caeca are really very degenerate sipbonozooids, for 

 they are identical in origin with the less degenerate sipbonozooids of Sc. capitale, Sc. densuni, 

 and Sc. hiftum, in which species the sipbonozooids possess a small stomodaeum and traces of 

 mesenteries. 



Canal Systems. The transverse vessels of the superficial canal system are very pro- 

 nounced but they are not quite so broad as in Sc. capitale, averaging •! mm. and lying 

 about '15 mm. below the surface. The vessels of the internal system are fairly numerous, 

 and are very broad near the surface, where as in other species they usually terminate in 

 the transverse vessels of the superficial canal system. 



Zoochlorellae are very numerous in that portion of the endoderm of the transverse 

 vessels which lies near the surface. It is so distended by their presence as to almost 

 obliterate the lumen of the canals. They are not numerous in the vessels of the internal 

 canal system, except where they approach the surface. They are also present in considerable 

 numbers in the endoderm of the autozooids, but they are not so numerous in any part 

 of the colony as they are in Sc. gardineri. 



The mesogloea is diffuse and does not stain very readily with borax-carmine or haema- 

 toxylin owing to the sparcity of spicules in the lobes, it is more abundant there than in 

 many other species. 



The interesting features of this species are (1) the colony is tough and fleshy in texture ; 

 (2) the spicules are not very numerous, and are small compared with those of many other 

 species; (3) the autozooids are fairly large. The tentacles are longer than those of any 

 other species in the collection, and have a double row of minute pinnules do^vn each side. 



