1 6 Lightbown, Filaments in the Siphonozooids of Pennatulacea 



hat jedes eine geraumige Leibeshohle mit 8 Septa, die unterhalb 

 des Magens in einen kurzen Kanal sich fortsetzt, an dem ich eben- 

 falls keine Filamente finde. " 



In Ptilosarcus Gurneyi, Gray, now called L. Gurneyi, Gray (vide 

 Hickson p. 188) Kolliker did find two mesenteric filaments "of 

 tolerable length" and subsequently cited the occurence of them as 

 one of the diagnostic characters of the genus Ptilosarcus. (1872, 

 p. 368). 



In the same writer's account of the British Museum specimen L. 

 sinuosum ( = Ptilosarcus sinuosus, Gray) there is no statement 

 regarding the filaments of the siphonozooids, but in L. Grayi 

 (— Sarcoptilis grandis, Gray) their absence is noted. (I.e. p.368). 



Scytalium Balssii, Hickson. 



,, Martensii, Kolliker. 



,, Sarsii, Herklots. 



Filaments are absent in the siphonozooids of the three above 

 species. 



Ptereoeides argenteum, Ellis and Solander. 

 ,, caledonicum, Kolliker. 



,, griseum, Bohadsch. 



, , MALAYENSE, Hickson. 



,, speciosum, Kolliker. 



,, timorense, Hickson. 



Filaments are absent in the siphonozooids of all the above 

 Pteroeides species. 



Pteroeides pellucidum, Kolliker. 



Siphonozooids situated on the lower surface of the leaves are 

 stated to possess mesenteric filaments by Kolliker (1872, p. 38) 

 with the qualification — "Doch sah ich sie bei einzelnen Individuen 

 auch fehlen und weiss ich nicht, ob denselben ein allgemeines 

 Vorkommen, bei den verschiedenen Arten zuzuschreiben ist. " In 

 other zooids of the colony they are absent. 



Pter. Steenstrupii, Kolliker. 



The siphonozooids on the leaves of this species are not densely 

 crowded in "plates" but occur scattered apart, some singly, others 

 in small groups of six or fewer. Filaments are present in them on 

 both upper and under surfaces of the leaf, and while these filaments 

 are of approximately uniform breadth (0.023 m.m. — 0.018 m.m.) 

 there is considerable variation in length (0.032 m.m. — 0.352 

 m.m.). 



