ON GLTCIPHAGUS DOMESTIC US AN'D (i. SPINIPES. 



285 



LiCHENOPORA HoLDSwoRTniT, Busk. (PI. XV. figs. 7 & H.) 

 Discoporella Holdsworthii, Bush, Cat. Mar. Polyzoa, pt. iii.p. 33, 

 pi. XXX. fig. 4. 



Lichenopora Holdsworthii, Waters, Quart. Journ. Geol. Soc. vol. xliii. 

 p. 34/ ; Ann. Mag. Nat. Hist. ser. 5, vol. xx. p. 261. 



I have already (Quart. Journ. Geol. Soc. xliii. p. 347, and else- 

 where) alluded to the " rays " in the zooecial tubes and cancelli, 

 and to Mr. Busk perhaps referring to these when lie speaks of 

 stellate pores 



The ovicell occurs as a central inflation with large roundish 

 depressions closed with a perforated pellicle. It spreads in 

 between the radii in somewhat the same manner as in L. califomtca 

 though not so marked on the surface. I have only seen the one 

 ovicell; and if this was the only specimen of L. Holdsicortliii 

 known, I doubt if it would be possible without breaking up the 

 specimen to decide wliether there was an ovicell. 



Loc. Living : Ceylon ; Victoria ; ' Challenger ' station 142 (S. 

 Africa). Foss 1 : Waipukurau (New Zealand). 



EXPLANATION OF PLATE XV. 



Fig. 1. Lichenopora californica, Busk. Showing ovicell extending between the 



radii. From Port Western (Victoria). X 12. 

 2. Caiicellus of L. echinata showing denticles. X 85. 

 '6. Lichenopora echinata, MacGr. Shows to the left the lower surface of the 



ovicell formed by reticulated cells covered with a pellicle. The upper 



surface is pitted. X 25. 



4. Lichenopora victor iensis. Shows ovicell and two ovicellular ducts. From 



Port Stephens, 5-6 fath. (New South Wales). X 25. 



5. Discotiobigera lineata, MacG. Sliows the ovicell at the border of the 



colony, and also the ovicellular duct. Fi*om Port Jackson (New South 

 Wales). X 25. 



6. Lichenopora echinata. Shows the formation of the ovicell which starts 



from several points to meet over the centre. From Port Phillip. X 12. 



7. Cancellus of L. Holdsworthii, showing rays. X 85. 



8. Lichenopora Holdsworthii, B., with ovicell. From Port Phillip. X 25. 



liesccirches into the Life-histories of Glycijjhagus domesticus and 

 O. spinipes. By A. D. Michael, E.L.S., F.Z.S., F.E.M.JS. 

 [Eead 3rd May, 1888.] 

 (Plate XVI.) 



For over three years last passed I have been, as opportunity 

 offered, endeavouring to elucidate certain obscure points which 

 I had observed in the post-embryonic development of the common 



