REPORT ON THE POLYZOA. 17 



Melicerita atlantica, Busk (PI. II. fig. 18). 



Melii-erita atlantica, Busk, Zool. Cliall. Exp., part xxx. p. 96, pi. xiv. fig. 1. 



There is a thickening of the calcareous wall round the ovicellular opening. There is 

 one large distal rosette plate near the base of the wall, and two large lateral rosette plates, 

 thus giving connection to each of the neighbouring zooecia. This seems to be allied to 

 .several cretaceous fossils. 



Melicerita (?) dubia, Busk (PI. II. fig. 19 ; PI. III. figs. 24 and 35). 



Melicerita dubia, Busk, Zool. Chall. Exp., part xxx. p. 97, pi. xxxiiL fig. 10. 



I certainly do not consider that this is Melicerita, but as it is difiicult to say at pre- 

 sent where it should be placed, it may be better merely to discuss it under Busk's name, 

 though the name cannot be permanently retained, seeing that Pustulopora dubia. Hag., 

 is probably Melicerita. 



In a specimen in Edinburgh there are no avicularia, and I was only able to find two 

 in the British Museum specimen. The operculum, which is of a Membraniporidan 

 character, with a projecting edging over the upper part, is situated in the membrane 

 covering the zocBcium, and has not any direct connection with the calcareous wall. 

 There is one rosette plate in the distal wall situated near the base, and one large lateral 

 rosette plate. 



This is an interesting specimen, as there are many fossils from the chalk of this type, 

 but I have not yet been able to identify it with any. It is related to Eschara cymodoce, 

 d'Orbigny,' but is larger; also to Eschara dryaf and to Eschara cyclostoma, Hagenow.' 



Calwellia sinclairii. Busk (PI. I. fig. 5). 



Onchophora sinclairii. Busk, Zool. Chall. Exp., part xxx. p. 103, pL x. fig. 4. 



The " lunate pore " does not open into the zooecial cavity, but into a separate 

 chamber. This was first perceived in the spirit specimens without making any prepara- 

 tions, but microtome sections showed that the thin membranous wall starts from just 

 above the pore. The chamber is empty, and I have not found any muscles in it, 

 whereas there are numerous muscles attached to the membrane enclosing the tentacles 

 and stomach. 



The signification of this chamber is not clear, and can only be completely studied in 

 living specimens with the tentacles expanded ; but we have now three kinds of pores on 

 the front of the zooecia, viz., the peristomial, the suboral opening into the body cavity, 

 and the present, which, until we understand its meaning, we may call a cameral pore. 



1 Pal. Fr., p. 156, pi. 674, figs. 10-13. ^ op. cit., p. 168, pi. 677, figs. 7-9. 



' Bry. Maast. Kr., p. 75, pi. ix. figs. 7, 8 ; pi. xii. fig. 3. 

 (zool. chall. e.\p. — PART Lxxix. — 1888.) Kkkk 3 



