PROGRESS OF MICROSCOPICAL SCIENCE. 267 



be arrived at by watching the changes through which they pass in the 

 course of their development, research has been vigorously turned in 

 this direction, and although an immense mass of facts has long since 

 been accumulated regarding this question, Parker's brilliant researches 

 on the develojjment of the skull give an indication of the gi'eat things 

 we may yet anticipate from this kind of research. " Speaking of micro- 

 scopical study before this audience, I cannot but remember that in this 

 country more than in any other we have a number of learned gentle- 

 men who, as amateurs, eagerly pursue investigations in this dejmrt- 

 ment. I confess that I am always sorry to witness the enthusiastic 

 perseverance with which they apply themselves to the prolonged study 

 of markings upon diatoms, seeing that they might direct their elfurts 

 to subjects which would repay them for their labours far more grate- 

 fully. I would venture to suggest to such workers that it is now more 

 than ever necessary to abandon all aims at haphazard discoveries, 

 and to aj^proach microscopy by the only legitimate method, of under- 

 going a thorough preliminary training in the various methods of 

 microscojiical investigation by competent teachers, of whom there are 

 now plenty throughout the country." 



Pakeontology and Embryology united by Evolution. — Professor 

 Allman, F.R.S., in perhaps the ablest address that has been given for 

 many years to the British Association, afforded an admirable illustra- 

 tion of the importance of evolution in bringing two branches of 

 science to bear on each other. He said that through the hyiiothesis 

 of evolution, palaeontology and embryology are brought into mutual 

 bearing one on another. Let us take an example in which these two 

 principles seem to be illustrated. In rocks of the Silurian age there 

 exist in great profusion the remarkable fossils known as graptolites. 

 These consist of a series of little cups or cells arranged along the 

 sides of a common tube, and the whole fossil presents so close a 

 resemblance to one of the Sertularian hydroids which inhabit the 

 waters of our present seas as to jusrtfy the suspicion that the grapto- 

 lites constitute an ancient and long since extinct group of the 

 Hydroida. It is' not, however, with the jDroper cells or hydrothecfe 

 of the Sertularian s that the cells of the grajitolite most closely agree, 

 but rather with the little receptacles which in certain Sertularinae 

 belonging to the family of the Plumularida we find associated with 

 the hydrothecsB, and which are known as " Nematophores " ; a com- 

 parison of structure then shows that the graptolites may with con- 

 siderable probability be regarded as representing a Plumularia in 

 which the hydrothecfe had never been developed, and in which their 

 place had been taken by the nematophores. Now, it can be shown 

 that the nematoj)hores of the living Plumularida are filled with masses 

 of protoplasm which have the power of throwing out i^seudopodia, or 

 long processes of their substance, and that they thus resemble the 

 Ehizopoda, whose soft parts consist entirely of a similar proto2)lasm, 

 and which stand among the Protozoa, or lowest group of the animal 

 kingdom. If we suppose the hydrotheca suppressed in a j^lumularian, 

 we should thus nearly convert it into a colony of Ehizopoda, from 

 which it would differ only in the somewhat higher morphological 



