688 YOUNG SPECIMEN OF ORXITHORHYXCHUS AXATINUS, 



sible yet to determine the sex of the specimen, as the external 

 characters are insufficient. 



The tail ' is flat ventrally and convex dorsally. It measures 

 1 1 mm. in length and 6 mm. in its maximum breadth. 



As Professor W. Newton Parker* has so recently instituted a 

 comparison between the young mammary foetus oiEchiihia and that 

 of Ornithorhi/nchus, it is unnecessary for me again to call attention 

 to the interesting resemblances and comparatively slight differences 

 in external characters between them. I cannot, however, agree 

 with Professor Parker in his remarks concerning the horny 

 character of the snout in either young or adult Monotremes. 

 Thus he indicates as a point of similarity between the young of the 

 two genera that in each case the snout is " horny and immobile," 

 and he states that in the older of his stages of the Echidna the 

 " horn " is thicker than in the younger. Upon this he observes 

 " this is the more remarkable as in the adult the skin in this 

 region can hardly be said to be horny at all." Most certainly it 

 cannot. ISTo epithet could well be further from the mark than 

 " horny " as applied to the skin of the snout of the adult Echidna, 

 which is, on the contrary, a very soft and delicate skin, wrinkly 

 and freely movable upon the deeper parts. 



But I cannot understand why the term " horny " should be 

 applied to the general epidermis of the snout of the foetus in 

 either genus. The snout of the foetal platypus dealt with in this 

 paper is at all events no more " horny and immobile " than is that 

 of the young mammary foetus of a marsupial, with this sole 

 exception that over the very limited area of the caruncle the 

 corneous epidermis is perhaps a little thicker and denser than 

 elsewhere. Sections of the snout which have lately been made 

 show that, except over the above area, there is no j'-ellow reaction 

 at all to a double stain of picric acid and haematoxylin, and the 

 stratum corneum is relatively quite a thin layer, even over the 

 caruncle, where, however, it does show the yellow picric stain 

 indicating a process of cornification. Further I have in my 



* P.Z.S. June, 1894. 



