490 MR. A. W. WATERS ON 



occlusa B., are 60 times as long. In many cases there seems to 

 be no mandible, only a disk, to which the peculiar body is attached, 

 and this peculiar body is relativ^ely very large. Smitt refers to 

 the mandible of the Floridan specimens often being wanting, 

 " presenting the opening closed only by a membrane." 



There is no possibility of knowing what the Cellaria tenella of 

 Lamarck was, and it certainly may have been Cellaria *, so that, 

 as I have previously said, it is better to retain the name oculata. 

 The genus Nellia was not satisfactorily described, and therefore 

 various authors have adopted the genvis Farcimia of Pourtales 

 and Smitt. Fleming had made a genus Farcimia which might 

 include Nellia, but as he made it for Cellaria, with C. fistulosa 

 as type, it was always a superfluous genus, and Smitt considered 

 it non-existent. Although Levinsen adopts Nellia, it seems 

 better to adhere to Farcimia, the name used in my recent papers, 

 and which has been used by most workers recently. 



Loc. See my paper referred to, and add Wasin, Brit. East 

 Africa, 10 fatti. (501) ; Prison Island, Zanzibar Channel, shore 

 (503), 10 fath. (505) ; Has Osowamembe, Zanzibar Channel, 

 10 fath. (504) ; Meweni Bay, Zanzibar, 6 fath. (510); Chuaka, 

 Zanzibar, 3 fath. (526), collected by Crossland. Texas and 

 St. Thomas, W. Indies (^Levinsen). 



DiPLODIDYMIA COMPLICATA Reuss. (PL LXYII. figs. 11-15, k 

 text-fig. 79.) 



Diplodidymia complicata Reuss, " Foss. Fauna der Oligoc. von 

 Gaas," Sitzungsber. d. k. Ak. der Wissensch. Wien, math.-nat. CI. 

 vol. lix. Abth. i. p. 469, pl. iii. figs. 6-9 (1869). 



Micropora ratoniensis Waters, Ann. Mag. Nat. Hist. ser. 5, 

 vol. XX. p. 185, pl. iv. fig. 5 (1887). 



Micropora articulata Waters, Quart. Journ. Geol. Soc. vol. xlvii. 

 p. 14, pl. ii. figs. 5, 6 (1891). 



From Chuaka, Zanzibar, there are several pieces throwing 

 light on this form, which has only been seen in fragments 

 previously. 



The zoarium has a stalk consisting of long barren internodes, 

 sometimes as many as eight, followed by long articulated inter- 

 nodes with the zocecia placed diagonally on the four sides. The 

 contents of the barren internodes send out a branch to the 

 surface, jvist as we have seen in Chlidonia cordieri Aud. From 

 near the starting-point of each sub-colony a number of narrow 

 radicles radiate, and sometimes from one of these radicles a 

 fresh sub-colony grows, as is frequently the case in species with 

 creeping stolons. 



The branches are dichotomous and articulated, having two 

 chitinous tubes forming each articulation. Occasionally ther6 

 are more than the four rows, but this will only be for a short 

 distance near the articulation, and in one piece there is a median 



* Busk gives it with ?s3'non}'m of Cellaria gracilis Busk. 



