474 
BULLETIN 106, UNITED STATES NATIONAL MUSEUM. 
Genus MUCRONELLA Hincks, 1880. 
1S80. Mucronella Hincics, British Marine Polyzoa, p. 360. 
The frontal is surrounded by areolae and covered by a plenrocvst, costulate or 
granular. There is a lyrula and often some cardelles in the peristomice interiorly. 
Fig. 133. — Genus Mucronella Hincks, 1880. 
A-G. Mucronella peachi Johnston 1S47. A. Zooecia, X 50. B. Zooecia with ovicells, X 
25. C, D. Old conditions, X 50, showing the growth of the pleurocyst over the surface E. Sep- 
ta lae, X 18. (A-E after Hincks, 1SS0. ) F. Operculum, X 60. ( After Leyinsen, 1894.) 
G. Lyrula, X 50. (After Waters, 1889.) 
H-U. Lyrulae, species of Mucronella. H-I. M. ventricosa Hassall, 1841, X 50, and X 85. 
(After Waters, 1889.) J. M. labiata Boeck, 1861, X 85. (After Nordgaard, 1861.) K. M. 
abyssicola Norman, 1S6S, X 85. L. M. laqueata Norman, 1S68, X 85. M. M. peachi Johnston, 
1847, X 85. (K-M after Nordgaard, 1905.) N. M. porom Hincks, 1881, X 50. O. M. variolosa 
Johnston, 1838, X 25. P. M. elleri MacGillivray, 1868, var. biaviculata Waters, 1889, X 50. 
Q. M. biincisa Waters, 1S82, X 50. R. M. rostrata Hincks, 1880, X 50. S. M. levis MacGilli- 
vray, 1882, X 25. T. M. spinosissima MacGillivray, 1879, X 25. U. M. d-iaphana MacGillivray, 
1879. X 50. (N-U after Waters, 1889.) 
Genotype — Mucronella ( Lepralia) peachi Johnston, 1847. 
Range. — Jacksonian -Recent. 
The limits of this genus were rigorously established in 1904, by Waters. It 
differs from Smittina in the replacement of the avicularium by a mucro, that is to 
say, by an organ which we know to be almost equivalent. 
