flOLLESTON <>\ OOH^ELATIOlTfi OF OEOWTH. 1^7 



Inhere can nt nil etente be no doubl Ihal they were developed 

 i'vivw the genera] fbririative mass of blafctema, whicli Burrounds the 



aorta m the fetus, as described by Profe ■ ( toodsir;* and thai there' 



fore the} were morphologically as well as physiologically bo bed 

 with the bhymmt This gland, as well aid the thyroid, was largely 

 developed in (Ins specimen, and the arrangement Of the two eiancra 

 coincided very exactly with the description given of them by my 

 friend Mr. Turner.^ 



The lymphatic glands generally thrOughoirl the body were largely 

 developed; so largely, In met, at either jaw angle, as to simulate tho 

 appearance of a large submaxillary gland. 



The spleen waS, as lias been so often described, curiously multifid. 



All oi' these ductless, all of these lymphatic, glands were richly 

 supplied with blood vessels; all, alike and jointly, laboured at tho 

 elaboration of the constituent elements of the vast mass of this 

 cetacean's blood. They enabled it thus to support a high standard 

 of temperature in an excellent conducting medium, and they sup- 

 plied all the calls for rich and refined aliment which a brain equalling 

 in this case one-sixtieth of the weight of the entire body, made 

 upon the nutritive fluids. They may be taken as illustrations of 

 " tautogeneous growths' 1 of the first of our two classes. 



Many of Mr. Paget's instances of complemcntal nutrition, 3I>. 

 Darwin would explain as the results§ of hereditary transmission, 

 with modification, and there can be little doubt that of the two 

 hypotheses the latter will, to many minds, seem to suit the better 

 with such instances as the four rudiments of nails on the fun of 

 the Manatee, or the equally rudimentary teeth in the Ruminant's 

 intermaxillaries, or of the representatives of the Polian vesicles in 

 the Arenicola. 



But many of Mr. Paget's instances cannot be brought under 

 this head, and constituted as our minds are, we cannot but read them 

 as he has done. 



Mr. Darwin, on the other hand, himself || admits that there are 

 many instances of correlated growths of which our reason can gi\e 

 no rationale, either as subserving ends, or as confirming to type, or 

 as speaking of parentage, or as working up into structure what wonld 

 else be waste and excretory; for which in other words it can assign 

 neither final nor formal, nor material cause. I would instance in 

 addition to those he brings forward, the correlations of growth wit- 

 nessed in Morbus Canaileus betwixt a malformation bf the heart and 



* Phil. Trans. 184G, p. 038. 



f In the common Shrew, however, two bodies are to W (bond, floating loosely in 

 the abdominal cavity, but anchored each by a process of mesentery which is attached 

 just where these bodies in fche Porpoise lie fixed; ami that tiny are connected with 

 the lymphatic or rather with the lacteal Bystem, an examination of a Shrew, which 

 has died whilst digesting, will leave no doubt. 



% Transaet. Royal Soc. Edinburgh, Vol. XXII. Part ii. 



§ Origin of Species, p. 453-404, 1st edit. pp. 486-48?, 3rd edit. 



11 Origin of Species, pp. 145, 197, 1st edit.; pp. 162, 217, 3rd edit. 



TOL. I. — N. II. K. 3 R 



