30 * Zoological Society. 



terior half of the shell. The mouth is seated between the base of 

 the arms. The cesophagus passes obliquely through the tendinous 

 wall of the viscera in a direction towards the upper valve : it be- 

 comes slightly dilated, and is then surrounded by the liver. The in- 

 testine is continued straight to the opposite end of the visceral ca- 

 vity, is there again contracted, makes a sudden bend upon itself, 

 and returns to the middle of the right side of the visceral belt, which 

 it perforates obliquely, and terminates between the lobes of the 

 mantle a little below the bend of the arm. The liver is of a beau- 

 tiful green colour, and consists of a congeries of elongated fol- 

 licles, closely compacted together, which communicate by numer- 

 ous orifices with the stomach. As in Terebratula, there is no sali- 

 vary gland. 



In Lingula Audebardii, Brod., there is also no salivary gland: and 

 Mr. Owen is therefore disposed to believe that the gland described 

 as such in Ling, anatina by Cuvier, was only a portion of the liver, 

 from which the colour had probably been removed by long macera- 

 tion in spirit. 



In the want of salivary glands the Brachiopoda would agree with 

 the ordinary Bivalves. Destitute, like them, of any hard parts about 

 the mouth for comminuting alimentary substances, glands for 

 pouring in a fluid to blend with the food during that operation are 

 not wanted. 



The nervous system in Terebratula was not detected by Mr. 

 Owen. In Orbicula two small ganglia were found on the side of the 

 cesophagus next the perforated valve ; from which two filaments, ac- 

 companying the cesophagus through the membranous wall, imme- 

 diately diverge and pass exterior to the anterior shell muscles, pro- 

 ceeding with corresponding arteries to near the hearts, beyond which 

 he could not trace them. A single small ganglion is situated on the 

 opposite side of the cesophagus, but on a plane posterior to the pre- 

 ceding; this is probably the cerebral ganglion for giving off nerves to 

 the free spiral extremities of the arms, close to the base of which it 

 is situated. 



Mr. Owen exhibited, in illustration of his paper, drawings of the 

 several objects described in it. 



The following Notes relative to the period of Uterine Gestation 

 and the Condition of the new-born Foetus in the Kangaroo, Macro- 

 pus major, Shaw, were read by Mr. Owen. 



" Perhaps there is no question in animal physiology that has 

 given rise to more numerous and contradictory theories, and in 

 which fewer facts have been well ascertained, than that which re- 

 lates to the generation of the Marsupial Animals. 



"In the present communication I propose to limit myself to the 

 narration of some of the circumstances that have occurred in eluci- 

 dation of this subject during a series of observations which have 

 been made at the Gardens in Regent's Park during the past summer. 

 " All the Kangaroos at the Farm were for this purpose transferred 

 from the Farm to the Gardens at the latter end of June. The whole 

 stock consisted of two males and six females, all fully grown. The 





