47G 
BULLETIN 106, UNITED STATES NATIONAL MUSEUM. 
Genus RHAMPHOSTOMELLA Lorenz, 1886. 
A-G. Rhamplwstomella costata Lorenz, 18S6. A. Zooecia, X 30. (After Lorenz, 1886.) 
B. Section showing the oral glands terminating near the diaphragm, X 85. C. Gland, X 250. 
D, E Operculum and avicularian mandible, X 85. (B-E after Waters, 1900.) F, G. Oper- 
culum and avicularian mandible, X 60. (After Lorenz, 1886.) 
H-K. Rhamphostomella plicata Smitt, 1867. H. Ovicell and the anterior part of the 
zooecium, X 50. (After Nordgaard, 1906.) I, K. Operculum and avicularian mandible, X 
85. (After Waters, 1900.) J. Avicularian mandible, X 83. 
L. Avicularian mandible, X 85. 
M. N. Rhamphostomella contigua Smitt. 1S67. Operculum and avicularian mandible, X S3. 
O. Rhamphostomella scabra Smitt, 1867. Avicularian mandible, X S3. • (J-0 after Nord- 
gaard, 1905.) 
P, Q. Rhamphostomella radiatula Hincks, 1877. Avicularian mandibles, X 250. (After 
Lorenz, 1886.) 
It. Rhamphostomella bilaminata Lorenz, 1886. Avicularian mandible, X 150. (After 
Lorenz, 1S86. ) 
S, T. Rhamphostomella spinigera Lorenz, 1S86. Different forms of lyrula, X 83. (After 
Nordgaard, 1906.) 
The operculum closes the ovicell, which is hyperstomial ; it is thin and delicate, 
hut there is a raised circular ridge. There is a very narrow lyrula. before an 
asymmetrical sinus. The frontal is a pleurocyst with costules. Before the orifice 
of the ovicell and at the same height, there is a very large avicularium, oblique. 
