1882.] 
451 
[Kingsley. 
Fie. 5. Eecr with sixteen blastomeres showing the differentiation into 
epiblast and hypoblast. 
Fig. 6. The smaller or epiblast cells have about half enveloped the 
hypoblastic elements. 
Fig. 7. Egg at close of segmentation, the place where the hypoblast 
was last seen (the blastopore) being indicated by the letter “ b.” 
Fig. 8. Embryo showing the formation of tail fold. 
Fig. 9. Embryo artificially removed from egg membranes showing the 
notochord, medullary cord, and hypoblast, in the tail. 
Fig. 10. Later embryo in the egg. 
Fig. 11. Embryo just hatched, tapole stage. 
Fig. 12. Vacuoles in tail resulting from a disintegration of the noto- 
chord. 
Fig. 13. Same embryo three hours later, showing the contracted tail 
and the rudiments of the processes before attachment. 
Fig. 14-17. Subsequent stnges after attachment. 
Fio\ is. Young Asciuian three weeks after fig. 17, the caudal sheath 
O O o 7 
not wholly gone. 
Fig. 19. Young a week later than fig. 18. All of the principal organs 
outlined and the general structure of the adult attained. 
Mr. Samuel Wells read a letter from Mr. Frederick Habirshaw 
presenting his collection of Diatomaceae, consisting of 1678 species 
arranged in 66 boxes. Mr. Wells said that he congratulated 
the Society upon the acquisition of this valuable collection. 
It contains not only all the common species, both marine and 
freshwater, but many of the rarer species, some of which it would 
be almost impossible to duplicate. The greater part of the slides 
are preparations containing single species, many of them having 
a few frustules mounted in the centre of the slide. 
In the comparatively few cases of general mounts the particular 
species intended to be shown is indicated by a circle on the glass 
cover or by Maltwood’s finder. The authenticity of the nomencla- 
ture is assured by the facts that most of the slides are from the 
preparations of Prof. Hamilton L. Smitjr, Mr. Christian Febiger, 
Mr. Eulenstein and Messrs. Cleve and Muller, and have all been 
examined by Mr. Habirshaw. 
The arrangement of slides in the collection, as well as in the 
catalogue, is alphabetical, following that of Mr. Habirshaw’s “ Cat- 
alogue of the Diatomaceae,” so that any desired species can be 
readily found. 
