BICENTENARY OF LINN^US 27 



but also the aquatic Vivipara now called Cetaceans and Sirenians, were for 

 the first time definitely included under a single class name. 



In attempting to appraise Linnseus's contributions to the broader loiowl- 

 edge of the class of mammals, we must bear in mind what Dr. J. A. Allen 

 has well shown/ namely: that Linnaeus was primarily a botanist, that his 

 interest in mammals was incidental, that his opportunities for studying 

 them were very limited, that his first-hand knowledge of extra-European 

 mammals was practically nil, and finally that several of his ordinal group- 

 ings of mammals (e. g., rhinoceros with the rodents) now appear highly 

 unnatural and even ludicrous. 



On the other hand, there are certain considerations which may prevent 

 us from thinking any the less of his judgment and genius on that account. 

 Although Linnaeus may have known very little about extra-European 

 mammals, he had, nevertheless, a fairly good conception of the essential 

 features of mammals as a class, as shown by his definition in the tenth edition 

 of the "Systema Naturae" (1758). Here in concise phrase he states that 

 mammals have a heart with two auricles and two ventricles, with hot red 

 blood; that the lungs breathe rhythmically; that the jaws are slung as in 

 other vertebrates, but "covered," i. e., with flesh, as opposed to the "naked" 

 jaws of birds; that the penis is intromittent ; that the females are viviparous, 

 and secrete and give milk; that the means of perception are the tongue, 

 nose, eyes, ears and the sense of touch; that the integument is provided 

 with hairs, which are sparse in tropical and still fewer in aquatic mammals; 

 that the body is supported on four feet, save in the aquatic forms, in which 

 the hind limbs are said to be coalesced into a tail (the only erroneou.'^ idea 

 in the whole definition). 



Many of these characters had previously been noticed by Ray in his 

 description of the hairy quadrupeds. It is not impossible, too, that Lin- 

 naeus may have been assisted to the comprehension of the essential features 

 of the mammals through his friendship with Bernard de Jussieu, who is 

 said by Isidore Geoffroy Saint-Hilaire to have induced him to include the 

 Cetaceans in the class Mammalia; and possibly he also owed something 

 to the researches of Klein and Brisson. In spite of all this, Linnaeus's own 

 studies in medicine, in Holland, doubtless made him familiar with the 

 anatomy of at least one mammal, man; and on his journeys through the 

 north of Europe he must have observed many other mammals at close range. 

 Thus was Linnaeus prepared for the clear recognition and emphasis of 

 another fact of far-reaching importance. It was evidently well known 

 that the anatomy of the hairy quadrupeds was similar in plan, if not in detail, 



» See pp. 9 ff. 



