95 



shows on the contrary a tendency, as well as the most ingenious 

 means of execution, for adiversity of forms,) to fall into absolute 

 rules. What do we know of it? On the contrary, let us better un- 

 derstand our duties; let us constantly restrict ourselves to the con- 

 sideration of facts. It is a means of exposing ourselves to grave 

 mistakes, if we so easily and so precipitately determine with regard 

 to functions. In fact the Shreios alone share with the Monotremaia 

 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 IVater-Rat, vvhich possesses the sarae gland 

 at all seasons and in both sexes. 



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

 the nature of the localities, aąuatic 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 knovvn. To acquire a knovvledge of these facts 

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

 blematicpart 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 Shreivs offer }is another useful piece of instruction: 

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

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

 lands and take freely to the vvater; 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. Ovven addressed the Society. He špoke of the glands 

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

 the Monotremaia : in the IVater-Rat, the glands exist in both sexes, 

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

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

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

 bringing forth the young. To these impoi tant discrepancies is to be 

 added one still moreimportant — the glands referred to in the JVater- 

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

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

 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. Ovven adduced various 

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

 approaching to that ofcream. Simplicity ofstructure, 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 lovvest 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 Tiver. Such is 



