4 PROCEEDINGS OF THE NATIONAL MUSEUM vol. 122 



New zooids are formed at the periphery of the colony by the anas- 

 tomosis of thin-walled tubules that originate as simple evaginations 

 from the basal-lateral wall of young zoecia. The method is reminis- 

 cent of the budding pattern of Arachnidium jihrosum Hinks as de- 

 scribed by Prenant and Bobin (1956, p. 228; see also p. 224 and fig. 

 99). It is unlike the budding of Vidorella pavida Kent as described 

 by Braem (1951, p. 10) or that of Arachnidium irregulare Harmer 

 (1915, p. 49) in that the connecting tubules of these forms do not 

 anastomose. 



Filiform processes. — Early in development, even before the 

 first traces of the polypide have begun to appear, elongate evagina- 

 tions originate on the frontal surface of the zoecium (fig. 2). These 

 processes are conspicuous, even at the early stage shown in figure 2, 

 because a thick, dark coat of foreign material is already adherent to 

 them. In section these processes can be seen to be composed of the 

 following four layers: (1) an outermost layer of detritus and sediment; 

 (2) a cuticle; (3) epidermis; (4) a peritoneum. The processes are 

 clearly smiple evaginations of the body wall. Septa are lacking. 



Very similar, presumably homologous structures have been re- 

 ported from a number of related ctenostome species. These include 

 Arachnidium Jibrosum Hinks (1880, p. 511), Nolella sawayai Marcus 

 (1938, p. 52), Nolella horridum (O'Donoghue and O'Donoghue, 1926 

 p. 61), Nolella spinijera (O'Donoghue, 1942, p. 59), Arachnoidea 

 barentsia Kluge (1962, p. 212), and Cryptopolyzoon evelinae Marcus 

 (1942, p. 477). The structures have not been studied in detail and 

 each author has coined his own terminology without reference to other 

 species. As a result, the terminology has become cluttered by a 

 number of different terms for structures that are apparently homolo- 

 gous. These include the "lateral processes" and "filiform processes" 

 of Hinks (1880, p. 511), the "free encrusted appendages" of Marcus 

 (1938, p. 52), and the "spinous processes" of O'Donoghue (1924, p. 59) 

 and O'Donoghue and O'Donoghue (1926, p. 21). The "cuticular 

 appendages" described by Prenant and Bobin (1956, p. 227) for 

 Arachnidium Jibrosum include broader basal lobations that adhere 

 to the substrate, as well as erect, elongate processes. The structures of 

 Cryptopolyzoon evelinae called "adhesive papillae" by Marcus (1942, 

 p. 478) apparently include not only homologous elongations but 

 some true kenozoecia as well. The term "filiform process" seems the 

 most appropriate and is the name that will be used here for any filiform, 

 aseptate evaginations of the body waU. 



The filiform processes of Victor ella argilla are modified for the 

 accumulation of foreign material and secrete large quantities of an 

 adhesive substance that stains a bright turquoise in Alcian Blue 



