506 



EDITH M. PRATT. 



anatomy is valuable as a basis for the comparison of other species, and is of material 

 assistance in the establishment of certain generic features. 



Six species of Sarcophytum occur in the collection from the Maldive Islands, three of 

 which have been recorded from other localities, one is a new variety of an old species, and 

 two species are new. The species are : — glaucum, latum, hoettgeri, var. nov., roseutn, sp. nov., 

 tenuis, sp. nov. 



Siphonozooids. Owing to the difference in contraction of preserved specimens it is 

 difficult to obtain any specific standard of measurement of the autozooids. A series of 

 measurements of the siphonozooids of several specimens belonging to the same species, how- 

 ever, show them to be of almost uniform size. The size of a siphonozooid in the preserved 

 condition therefore appears to be almost constant for a species, and may be looked upon 

 as a specific character. The length of the stomodaeum of a siphonozooid varies to a certain 

 extent in different species, but is almost constant for a single species. It will be seen from 

 the appended table that the stomodaeum of the siphonozooids is an important factor in the 

 determination of the species'. 



By introducing lamp-black into the sea- water about living colonies of Sarcophytum, 

 Mr Gardiner observed currents entering the siphonozooids. After some time the blackened 

 water was ejected by the autozooids, and in some cases by the same siphonozooids, showing 

 that a reversal of the current had taken place within the colony. 



The presence of numerous, well-marked, and regularly arranged siphonozooids in this 

 genus as well as in the amended genus Lohophytmn, enables the effectual aeration of the 

 superficial portions of the colony, where metabolism is greatest, and is doubtless correlated 

 with the absence of a special superficial canal system so well marked in Sclerophytum, in 

 which the siphonozooids are very minute. 



Autozooids. The autozooids are large, and are very similar to those of Lobophytum. The 

 tentacles are much shorter and broader in proportion to their length than those of Alcyonmm. 

 They are of the simple pinnate character, with a single row of pinnules down each side. 

 In some cases the pinnules are so small as to be easily overlooked. They are very similar 

 to those of Lobophytum. 



The stomodaeum is usually long and in the preserved state is convoluted. The siphono- 

 glyph is not well-marked in any of the specimens in the collection, and can only be 



1 The measurements were obtained by measuring several 

 siphonozooids from diii'erent parts of a colony and taking 



- S. plicatm 

 Islands. 



; was not in the collection from the Maldive 



