8 Lightbown, Filaments in the Siphonozooids of Pennatulacea 



V. cynomorium. Pallas. 



In describing - the character of the genus Veretillum, Kolliker 

 (1872, p. 331) states that mesenteric filaments are present. (It may 

 be noted here that all Kolliker's statements on mesenteric filamenjts 

 are made as a generic character : it must be assumed therefore that 

 they apply to all the species whose descriptions follow, even though 

 in some cases it appears doubtful whether the author has verified 

 the statement for every species) . Kiikenthal and Broch describing 

 the same species (1911, p. 515) also mention their presence — "Die 

 zwei dorsalen Mesenterialfilamente laufen bis zu dem Grunde der 

 Leibeshohle hinab. ' ' 



Ver. (Policella) australis, Gray. 

 Ver. (Policella) manillensis, Kolliker. 



Of these species the following observation is made : 



"Die Zooide von Policella messen im Mittel in der Lange bis zum 

 Ende des Magens 0.18 - 0.20 m.m., in der Breite 0.36 - 0.45 m.m.,. 

 wovon 0.09-0.12 m.m. auf den innen mit Flimmern besetzten 

 Magen kommen und zeigen ihre Mesenterialfilamente von 0.028 

 -0.032 m.m. Breite keine bestimmte Stellung im Vergleich zum 

 Stocke. Die weiten Leibeshohlen der Zooide ragen mit ihren 

 Mesenterialfilamenten bis unter die Langsmuskeln der Cutis und 

 gehen hier in ein spongioses Gewebe iiber, dessen Abzugskanale in 

 den Zwischenwanden der Polvpenzellen zu verlaufen scheinen. "" 

 Kolliker, 1872 p. 320. 



Cavernularia elegans, Ilerklots. 



According to Kiikenthal and Broch, filaments are present on the 

 dorsal mesenteries (1911, p. 513). 



C. obesa, Milne-Edwards and Haime. 



This species affords a marked contrast to C. orientalis being 

 extremely fleshy and the siphonozooids densely crowded, renderings 

 investigation difficult. The filaments are slightly coiled and run 

 down the narrow zooid cavity closely parallel for an average 

 distance of 0.42 m.m. or about 2\ times the length of the 

 stomodaeum. Kiikenthal and Broch (1911 p.513) record the 

 presence of filaments in the species. 



C. orientalis, Thomson and Simpson. 



The filaments here are exceptionally well developed, and 

 are very readily perceptible owing to the transparency of the 

 tissues of the colony. In most of the siphonozooids these filaments 

 extend for an appreciable distance beyond the bases of the 

 coelentera into the subjacent canals. In an average sized siphon- 



