1887.] On the Young of the Ornithorhynchus paradoxus.. 391 



XY. " Description of a Newly-excluded Young of the Ornitho- 

 rhynchus paradoxus'' By Sir Richard Owen, K.C.B., F.R.S., 

 &c. Received May 20, 1887. 



(Abstract.) 



Of this interesting and long-hoped-for discovery the author was 

 informed by his friend and correspondent, the Baron von Mueller, 

 F.R.S., of the Botanical Gardens, Melbourne, and shortly received 

 the specimen from the Baron : also, further details from Mr. Le Souef , 

 of the Zoological and Acclimatisation Society's Office, Melbourne ; 

 and from the Rev. Pastor Hagenauer, Superintendent of the Mis- 

 sionary Station in Gipps-Land, S.E. Victoria, to whose influence 

 with the natives science is indebted for the acquisition, as I am to 

 Baron von Mueller for the reception, of the embryo well preserved in 

 alcohol. The specimen is nude, an inch in length, the nostrils well 

 opened, and between them the fleshy conical support of the horny 

 sheath, which has been shed and by which the chorion had been torn 

 open at birth. The mouth is a transverse slit, not produced as a 

 beak, bounded by flexible lips, and sufficiently open to receive nutri- 

 ment afforded by the group of pores excluding the secretion of the 

 mammary gland of the pouch. The fore limbs, chiefly represented by 

 the paws and pentadactyle, with claws sufficiently developed for 

 adhering to the part of the pouch on which the excretory pores open. 

 The hind limbs are less developed, have the five digits feebly indicated 

 and clawless. A short conical-pointed tail projects between them. 

 The elongate, flattened, natatory tail of the adult is a later develop- 

 ment. There is no trace of navel. The skin of the trunk is 

 uniformly smooth and nude. 



If this embryo should be a male, the spur of the femoral gland is 

 a defensive organ of later growth. 



The author refrains from dissection in hopes of receiving another 

 specimen ; and, after a detailed description of the external characters 

 of the unique specimen, refers to his paper "On the Uterine Ovum 

 of the Ornithorhynchus " in the volume of the ' Philosophical Trans- 

 actions ' for 1834, and on the " Mammary Glands " in the volume 

 for 1832. 



