104 BULLETIN 104, UNITED STATES NATIONAL MUSEUM. 



Plate 8. 

 Fig. 1. Rhabdammina irregularis. X 10. (After Brady.) 



2,3. Marsipella elongata. X 15. Photographs of two specimenB with a large 



percentage of sponge spicules. 

 4-6. Marsipella cylindrica. X 15. Photographs of specimene with rather more 

 sand grains than usual for this species. 



Plate 9. 

 (After Heron-Allen and Earland.) 

 Fig. 1. Technitella legumen. Showing external surface of test. 



2. Technitella legumen. Section of test showing internal surface. 



3. Psammosphaera rustica. Type-specimen. 



4. Psammosphaera rustica. Abnormal double specimen. 



5. Psammosphaera bowmanni. Type-specimen, side view. 



6. Psammosphaera bowmanni. End view. 



7. Marsipella spiralis. Type-specimen. 



8. Marsipella qjlindrica. Specimen showing club-shaped end. 



9. Marsipella cylindrica. A fragment of a specimen, showing a spiral arrange- 



ment of the constituent sponge spicules. 

 All figures X 40. 



Plate 10. 



(After Her on- Allen and Earland.) 



Fig. 1. Technitella legumen. Showing the differential arrangement of the sponge 

 spicules in the external and internal layers. The interstitial cement is 

 represented by the shading. X 140. 



2. Psammosphaera rustica. X 40. 



3. Psamviosphaera rustica. An abnormal triple specimen. X 40. 



4. Psammosphaera rustica. Detail showing the method of construction in a 



"panel " of the test. The central space has been filled in by a fragment of a 

 triaxial sponge spicule. The interstitial cement is represented by dark 

 shading. X 140. 



5. Psammosphaera bowmanni. X 40. 



6. Marsipella spiralis. X 40. 



7. Marsipella spiralis. Detail showing the loosely constructed terminal crown. 



The constituent spicules are not embedded In cement. X 95. 



8. Marsipella cylindrica. Specimen showing club-shaped end and elongated 



spicules. X 40. 



9. Marsipella cylindrica. Enlarged view of end showing details of construc- 



tion. 95. 



Plate 11. 



Fig. 1. Rhabdammina discreta. X 12. 

 2, 3. Rhizammina algaeformis. X 40. 



4. Bathy siphon fdiformis. X 12. 



5. Bathy siphon fdiformis. X 12. The lower portion showing the central cav- 



ity and the thickness of the wall. 



Plate 12. 



Fig. 1. Bathysiphonargenteus. Type-specimen. X 75. (After Heron- Allen and Ear- 

 land.) 



2. Bathysiphon argenteus. A portion of the tube. X 200. (After Heron-Allen 



and Earland.) 



3. Bathysiphon argenteus. A portion of the tube viewed as a transparent object. 



X 650. (After Heron- Allen and Earland.) 

 4-6. Psammosphaera parva. X 35. Photographs of specimens each with a single 



large sponge spicule. 

 7-10. Rhizammina indivisa. Photographs of specimens. X 15. 



