100 PROF. GULLIVER ON THE RED CORPUSCLES [Feb. 25, 



of Vertebrata, comprehending such a wide extent of subordinate facts 

 as to rise to all the dignity of a central one, small as it may appear, 

 is really a great addition to zoological science. Thus is plainly un- 

 folded the most universal and essential difference ever before dis- 

 covered between the Mammalia and oviparous Vertebrata ; for this 

 one minute point is in truth so large and extensive as to clearly cha- 

 racterize the divisions in question in any sex or at any age, which 

 not one of the old diagnoses can effect. Yet not even a glimpse of 

 this important truth, so readily reconciling the discrepancies of former 

 observers, was ever caught, during the contentions as to the presence 

 or absence of the nucleus, in this zoological point of view. 



And the present conclusion is alike extended and supported by the 

 discoveries of development for which we are indebted to Mr. Whartou 

 Jones, who has clearly shown that there is a similar difference in 

 this respect. But although his important researches ought to have 

 been well known in this country since 1845, they have been strangely 

 neglected, while the far less accurate and comprehensive observations 

 of Professor Kolliker have been imported and translated, and much 

 too generally adopted in England. In connexion with Mr. Wharton 

 Jones's conclusion, I may mention that one, two, three, or four mam- 

 malian red corpuscles may certainly form a nucleus of a cell, as 

 depicted by me in the ' Philosophical Magazine,' Sept. 1842, p. 170. 

 This observation has often since been imported from abroad, but 

 never with the least perception of its significance. 



And so " this vexed question of a nucleus " is at length not only 

 settled, but also placed at the service of systematic zoology. Ac- 

 cordingly, the two great divisions of the Vertebrate subkingdom are 

 here characterized as Vertebrata pyrencemata and Vertebrata apy- 

 rencemata — the former corresponding to the oviparous, and the latter 

 to the Mammalian section. 



DESCRIPTION OF THE WOOD ENGRAVING (p. 101). 



All the corpuscles are drawn to a scale of 4^0-*'^ of ^° English inch, and are 

 magnified about 920 times linear admeasurement. The scale is marked at the 

 bottom of the engraving. 



Corpuscles only of average size are given ; and but one corpuscle from each 

 species of animal, with the few exceptions presently to be noticed. 



The corpuscles of Apyrensematous Vertebrates occupy the upper part of the 

 engraving, above the double line ; and the different orders of these are separated 

 by the short upright lines. The corpuscles of Pyrenaematous Vertebrates occupy 

 all the larger part of the engraving below the double line. At 12 is a row of 

 birds' corpuscles; 13-17, corpuscles of reptiles ; and 18, a row of the corpuscles 

 of fishes. The figures at 1 and 12, referring to structure, are fully explained at 

 page 93. Of the Pyrenaematous Vertebrates, the nuclei are shown much more 

 plainly than they appear in the pure corpuscles ; but the action of acetic acid ex- 

 poses the nuclei as distinctly as they are here represented. 



The names of the animals are set down in the following table, according to the 

 order in which the sketches of the corpuscles stand in the engraving. The fol- 

 lowing measurements of the corpuscles are all in vulgar fractions of an English 

 inch ; but as the numerator is invariably 1, it is omitted throughout, and the de- 

 nominators only are printed. T. denotes the thickness, L. D. the long diameter, 

 and S. D. the short diameter of the corpuscles. 



