104 MR. T. WHARTON JONES ON THE BLOOD-CORPUSCLE CONSIDERED IN 
Comparison between the Blood-corpuscle of the oviparous V jrtebrata generally, and that 
of Invertehrata. 
7- In the oviparous Vertebrata, from the Skate upwards, it has been seen that the 
blood-corpuscle in its different phases of development is essentially similar to that of 
the Skate. In the Invertebrata, from the Crab down as far as we have gone, it has 
also been seen that the blood-corpuscle in its different phases of development is essen- 
tially similar to that of the Crab. The only difference therefore in essential respects 
between the blood-corpuscle of the oviparous Vertebrata generally and that of the 
Invertebrata, is the same as that between the blood-corpuscle of the Skate and Crab, 
viz. that in the phase of nucleated cell, the latter does not attain to a decidedly co- 
loured stage. 
8. Hitherto I have altogether excluded the blood-corpuscle of the Mammifera from 
comparison with that of the Invertebrata; but such comparison I now proceed to 
make. 
Comparison between the Blood-corpuscle of Mammifera and that of Invertebrata. 
9. In the phase of granule-cell, the blood-corpuscle of the Mammifera and that of 
Invertebrata resemble each other in essential points of structure. In the phase of 
nucleated cell they also agree in the absence of a decided coloured stage ; in this re- 
spect differing from the blood-corpuscle of the oviparous Vertebrata generally and of 
the early mammiferous embryo. 
10. But here the resemblance between the blood-corpuscle of the Mammifera and 
that of the Invertebrata ceases. In common with the blood-corpuscle of the ovipa- 
rous Vertebrata, that of the Invertebrata differs from the blood-corpuscle of the 
Mammifera in not attaining to a decided third phase. The free cellseform nuclei 
which appear to exist in the blood of some of the Invertebrata, it has been above 
stated, can only be considered as abortions of such a phase*. 
* From neglecting the precautions above observed in instituting a comparison between the blood-corpuscles 
of the Vertebrata and those of the Invertebrata, Mr. Newport, in a communication recently made to the Royal 
Society, appears to me to have fallen into a very serious error, as to what corpuscles in the blood of insects and 
other Invertehrata are analogous to the “ red blood-corpuscles” of the Vertebrata. 
Overlooking altogether even the well-known differences between the “red blood- corpuscles” of the Mammi- 
fera and those of the oviparous Vertebrata, he assumes the “red blood-corpuscle” of the Mammifera as a 
standard by which to recognise in the blood of insects and other Invertebrata, any corpuscles which may be the 
analogues of the “ red blood-corpuscles” of the Vertebrata generally. 
Accordingly, finding in the blood of insects the elementary granules described in Memoir II. of this series of 
papers, pars. 19, 27, 36, 38, &c., and not being acquainted with the true nature of such particles, he has been 
misled by their similarity to his assumed type of “ red blood-corpuscles,” especially in respect of outward form, 
which is that of biconcave circular discs, into the conclusion that they are the analogues of the “ red blood- 
corpuscles” of the Vertebrata. 
The corpuscles in the blood of insects and other Invertehrata which, though little or not at all coloured, I have 
