14 Lightbown, Filaments in the Siphonozooids of Pennatulacea 



appended, exclusive of species which I have personally examined 

 and species synonymous with such. 



VlRGULARIA GLACIALIS, Sars. 



,, affinis, ( = V. Steenstrupii) Kolliker. 



,, Ellisii, Gray. 



,, elegans, Gray. 



, , pusilla, Verrill. 



,, gracilis, Gabb. 



,, elongata, Gabb. 



Confirmatory evidence of the lack of filaments in siphonozooids of 

 the species listed would therefore be valuable. 



V. juncea, Pallas. 



Siphonozooids do not possess filaments. 



V. mirabilis, Lamarck. 



An examination of longitudinal sections through the siphono- 

 zooids appeared to confirm the MarshahV statement (1882, p. 72) 

 that the stomodaea are blind sacs. There is no indication of 

 mesenteric filaments and if the above statement is correct the zooids 

 would appear to be functionless. The specimen I investigated was 

 however small in size, hence it is possible that with further growth 

 the stomodaea might acquire an opening into the body cavities. 



V. Rumphii, Kolliker. 



The siphonozooids occur in vertical rows between the leaves, and 

 in them mesenteric filaments are entirely absent. It may be noted 

 here that in the young zooids occuring in a groove near the base 

 of the rachis well developed dorsal mesenteric filaments were found. 

 This observation confirms the opinion expressed by Professor 

 Hickson (1916, p. 149) that these zooids are young or undeveloped 

 autozooids. When mature, autozooids possess eight mesenteric 

 filaments, but where development has been followed the fact has 

 been established that the dorsal ectodermic pair are the first to 

 appear. Accordingly, as mesenteric filaments are absent in mature 

 siphonozooids, their occurence in these undeveloped zooids coupled 

 with the fact of the presence of ) r oung gonads on the mesenteries, 

 appears to place Hickson 's interpretation beyond doubt. 



V. .Schultzei, Kiikenthal. 



The species is remarkable in the genus in having the siphono- 

 zooids on the leaves, and in the fact of these siphonozooids being 

 provided with short but well developed sinuous filaments. 



