58 Zoological Society. 



to functions. In fact the Shrews alone share with the Monotremala 

 this fact of resemblance, viz. that the monotrematic glands are more 

 developed in the female during the period of heat. The circum- 

 stances are different in the Water-Rat, which possesses the same gland 

 at all seasons and in both sexes. 



" Fourthly, What are we to infer from the distinction drawn from 

 the nature of the localities, aquatic as regards the Ornithorhynchus , 

 dry with reference to Echidna ? And why might it not happen that 

 the function should be modified according to the nature of the am- 

 bient medium ? Let us not establish a general thesis on facts which 

 are not accurately known. To acquire a knowledge of these facts 

 is our object, and our uncertainty with regard to them forms the pro- 

 blematic part of our controversy. We are dealing with a new fact) 

 let us wait till we have seen and learned it before coming to a definitive 

 conclusion. The Shrews offer us another useful piece of instruction : 

 they consist, in fact, of several species, all having the same gland, 

 but not inhabiting the same localities. Some do not quit the low- 

 lands and take freely to the water; while others are met with on the 

 dry soil of upland plains." 



The reading of M. GeofFroy-Saint-Hilaire's Paper having been 

 concluded, Mr. Owen addressed the Society. He spoke of the glands 

 adverted to by M. Geoffroy, as differing essentially from those of 

 the Monotremata -. in the Water-Rat, the glands exist in both sexes, 

 and at all seasons ; in the Shrews, they exist in the female only, and 

 are developed in the season of heat ; in the Monotremata, they exist 

 also in the female alone, but their development is at the period of 

 bringing forth the young. To these important discrepances is to be 

 added one still more important — the glands referred to in the Water- 

 Rat and in the Shrews are additional to those for the nutrition of the 

 young, and their function is wholly different : in the Monotremata 

 only one set of glands exists, and these are admitted by M. Geoffroy, 

 in his later hypothesis, to be for the secretion of nutriment for the 

 young. 



As regards the glands of the Cetacea, Mr. Owen adduced various 

 testimonies to show that their secretion is milk, of a very rich quality, 

 approaching to that of cream. Simplicity of structure, in a secreting 

 organ which is usually complicated, cannot therefore be relied 

 on as affording proof of a difference of function. All glands are 

 in their lowest condition, simple tubes, which become, in the 

 more highly developed forms of the gland, complicated in various 

 degrees, conglomerate or conglobate. Such is the case with the 

 organs for the secretion of bile, which commence in Insects in the 

 form of simple tubes, and passing through various stages of compli- 

 cation, become in the higher classes condensed into a liver. Such is 

 the case also with the pancreatic organ; a case more in point, as it 

 exhibits, within the compass of a single class, that of Fishes, all de- 

 grees of complication. In some it seems to be altogether wanting ; 

 in others it is rudimentary, consisting of one or two minute cceca 

 appended to the pylorus ; and these, in others, increase in extent, 

 in number, in complication, by becoming branched, and eventually 



