THE MORPHOLOGY OF THE CHEILOSTOMATA. 347 



Figs. 32—37. — Eutliyris obtecta, Hincks. — Torres Straits. 



Eig. 32. — Part of tlie frontal surface of a brand), showing two of the 

 large zocecia (b) ; m. c, marginal cavity of frond; a/ /c. /a, calcareous 

 papillae supporting llie frontal eititlieca : /?., pores. 



Fig. 33. — Basal view of a B-zocEciuin from which most of the basal 

 calcareous wall [h. to.) has been removed. The tentacles (^.), contained in 

 their tentacle sheath, lie in a groove of the compensation-sac {c.s.) which 

 bulges out on each side of the tentacles. The operculum [op.) is seen 

 partly through the distal wall {d. to.). 



Fig. 34. — Thick longitudinal section, showingtlie frontal epitlieca (e/;.) 

 and the basal epitheca {i. ep.) held at a distance from the calcareous walls 

 of the zooecia by the calcareous papillae {calc. p.). 



Fig. 35. — Basal view of a B-zooecium (b) and several others ; from the 

 edge of a frond. 



Fig. 3G. — B-zocecium and A-zooecium, calcined. The zooecia are in 

 contact with their neighbours by small parts only of their walls, which 

 are perforated by communication pores [c. p.). The remaining ])ores {p.) 

 are in relation with the cavity beneath the epitheca. 



Fig. 37. — Basal view of part of the marginal thickening of an old 

 brunch; z., zocecia; m., free margin of branch ; /.,/., longitudinal cal- 

 careous ridges. 



PLATE 17. 



Fig. 38. — Lepralia haddoni, n. sp. ; showing an avicularinm {acic.) and 

 the two kinds of opercula. — Torres Straits. 



Fig. 39. — L. haddoni. Basal view of azocecium with trifoliate o|)erculuni, 

 from the same slide ; m. ov., muscles of ovisac. 



Fig. 40. — Smittia re ticulata, J. MacGdl. ; showingtlie marginal areolae 

 («;•.). — Naples. 



Fig. 41. — Lepralia jiallasiana, Moll. Young zooecium. The comj)eiisa- 

 tion-sac {c.s.) is still small. The [)ores extend round the distal margin of the 

 operculum. — Naples. 



Fig. 42. — Smittia trispinosa, Johnst., var. arborea, Lev.; showing 

 the compensatiou-s:ic {c.s.). — Greeidand. 



Fig. 43.— Diagrammatic transverse section of a Flustrine form, showingtlie 

 parietal muscles (/;. m?) inserted into the frontal membrane {J'.m.). 



Fig. 44. — Similar section of a Cribrilina. Tlie frontal membrane is 

 covered by the frontal bars {/,Ij.) or costnles. 



Fig. 45. — Le])ralia dorsiporosa, Busk. The distal lobes of the frontal 

 shield (/. sli. d.) have nearly united on the distal side of the operculum. — 

 Torres Straits. 



