Miscellaneous. 249 



seems to me contrary to what we know most precisely of the mor- 

 phology of the circulatory apparatus. 



On the other hand, M. Wegmann had previously figured * and 

 described, in more detail than M. Boutan, a complicated system of 

 capillary vessels in Haliotis. Now H. Milne-Edwards long ago 

 announced that the organs of the Gasteropoda (except perhaps the 

 renal organ) always present lacunae and no capillaries. It was 

 therefore interesting to ascertain whether the branchia formed an 

 exception to this rule. 



By injections I have had no difficulty in reproducing the appear- 

 ances figured by M. Wegniann ; but I explain them by the well- 

 known foldings of the lamella and also by the nearly regular 

 arrangement in line of the connective cells or groups of such cells. 

 The supposed vessels of the two margins are only portions of the 

 lacuna in which the connective tissue is sparse and in which, con- 

 sequently, the injected material circulates easily. 



The space within the double basal membrane is therefore nothing 

 but a simple diverticulum of the general lacuna, which extends be- 

 tween the two laminae of the mantle. My investigations thus confirm 

 the views of Milne-Edwards. 



I may add that in the Aplysiidte and Bullidse the branchia is 

 formed by the more or less complicated folding of a single lamella, 

 the structure of which is the same as that just described for the 

 pectinate branchiae. — Comptes Benclus, August 8, 1887, p. 816. 



Description of a iieivly-excluded Young of the Ornithorhynchus 

 paradoxus. By Sir Richard Owen, K.C.B., E.R.S., &c. 



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

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

 F.E.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, Mel- 

 bourne ; and from the Rev. Pastor Hagenauer, Superintendent of 

 the Missionary 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 Miiller for the reception, of the embryo well 

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

 nostrils well opened, jnd 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 nutriment 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 suffi- 

 ciently developed for adhering to the part of the pouch on which 

 the excretory pores open. The hind limbs are less developed, have 



* Ibid. ser. 2, tome ii. pi, xix. 

 Ann. & Mag. K Hist. Ser. 5. FoZ. xx. 17 



