298 University of California Puhlications in Zoology, ["^ol. 4 



3. Those in which the peristome incloses a tooth or an avicularinni.... 4 



3. Those in which there is no inclosure Eetepora 



4. Those in which the peristome incloses an avicularium 7 



4. Those in which the peristome incloses a tooth Smittia 



5. Those with secondary orifice rising into a mucro Mucronella 



5. Those in which the secondary orifice does not rise into a mucro 6 



6. Those in which peristome is entire Phylactella 



7. Avicularium with rounded mandible Porella 



7. Mandible of avicularium not rounded Escharoldes 



Lepralia (part) Johnston. 



Lepralia Johnston, 1847. 

 Lepralia (part), Busk, 1854. 

 Lepralia, Hincks, 1880. 



Zooecia usually ovate, with the orifice more or less horseshoe- 

 shaped, arched above, contracted at 'the sides, with the lower 

 margin entire and generally slightly curved outward. Zoarium 

 inerusting, or rising into foliated expansions composed of one or 

 two layers. 



68. Lepralia bilabiata Ilincks. 



PL 21, figs. 61, 62, 63, 64. 

 Lepralia bilabiata Hincks, 1884, vol. 13, p. 49, pi. 3, figs. 1, la, lb. 



Zoarium forming a thick one-layered crust over stems or 

 shells, red in life, turning brown when placed in alcohol. Zooecia 

 short and broad, alternate, rounded above, truncate below; the 

 front wall at the outer growing rim almost wholly membranous 

 (pi. 21, fig. 61, im. zoe.) soon covered over somewhat more than 

 half its surface by a delicate calcareous front wall, granular, 

 white, convex; in older zooecia (fig. 62), rising into a keel, h., 

 extending from the lower rim of the operculum to the base of 

 the zooecium, and forming a thick rim, th. r., above the large 

 operculum, op. Zo«cia separated by faint, scarcely perceptible 

 brown lines, front Avail marked by radiating striffi and sometimes 

 rising into a distinct umbo, um. Operculum large, brown, oc- 

 cupying almost half the front surface of the zowcium, semicir- 

 cular above, with a strong rib on the edge ; curved on the lower 

 margin, where it is also strengthened by a chitinous bar ; the true 

 orifice (fig. 63, or.) inside the outer brown operculum, ou. op., 



