Manchester Memoirs, Vol. Ixii, (191 7) No. 4 11 



Chunella gracillima, Kiikenthal. 



In his description of this species in the memoir of the "Siboga" 

 Expedition (1916 p. 112) Hickson describes the siphonozooids 

 * 'found on the dorsal side of the swellings of the rachis that bear 

 the autozooids," and mentions that in them the mesenteries are 

 little developed, "but there appear to be two long mesenteric fila- 

 ments connected with the stomodaeum of each siphonozooid. " 

 Further it is stated that siphonozooids were not found on the rachis 

 between these swellings. Beyond confirming the observation of 

 filaments and noting that they were somewhat coiled, I have made 

 no further examination, but it would be interesting to determine 

 whether the siphonozooids described by Kukenthal and Broch in the 

 slender parts of the rachis between whorls of autozooids possess 

 filaments or not. 



Umbellula Antarctica, Kiikenthal. 



The siphonozooids on the rachis possess considerably coiled 

 dorsal mesenteric filaments. 



I examined a single preparation, made from this "Siboga" 

 specimen, of a piece of the body wall from the basal swelling of the 

 stalk. This tissue was stained in borax carmine, which is not very 

 satisfactory for the present purpose, but in it a few scattered 

 siphonozooids were discernable. This point is of interest in view of 

 the fact that their presence destroys the value of the morphological 

 diagnosis made by Jungersen (1904 p. 82) that "the zooidless part 

 of the bulb corresponds to the peduncle (i.e. stalk) of other Penna- 

 tulacea, and the greater part of the stalk from the beginning is to 

 be regarded as the rachis." This point is discussed by Hickson in 

 the ''Siboga" memoir (p. 118). For the purpose of the present 

 investigation I can make no dogmatic assertion on the presence of 

 mesenteric filaments in these basal siphonozooids : certain rather 

 yellowish sinuous bodies by the side of the stomodaeum in most of 

 the zooids bear a strong resemblance to filaments, but the fact thai, 

 they have absorbed little or no stain casts a certain amount of 

 doubt on their identity, and from lack of material I am unable to 

 make further preparations for confirmation. In my experience, 

 whatever the state of preservation, mesenteric filaments stain as 

 readily as the ectoderm of the stomodaeum, and to a greater extent 

 than the epithelium and mesoderm of the surrounding tissue. Fila- 

 ments would undoubtedly be of use in promoting circulation of 

 water in this fleshy part of the colony. 



Umbellula Carpenteri, Kolliker. 



The siphonozooids of the "petaloid" region of this species 

 possess filaments of unusually large size. The siphonozooids 



