Dr. Richardson on the Lurking Machete of New Holland. 175 



men described by Valenciennes*, but which Owen has also ob- 

 served f. 



5. That the number of the apertures of the pouches adjacent 

 to the pericardium is such as Valenciennes J has stated, so that 

 Owen § seems to have been mistaken with respect to their num- 

 ber. It has also seemed to us that the pouches do not commu- 

 nicate with the pericardium, but that they are blind sacs, with- 

 out any other apertures than those which communicate with the 

 branchial sac ; facts also observed by Valenciennes. 



6. That the anus is by no means situated as Valenciennes has 

 figured it II, viz. at the bottom of the fissure formed by the two 

 muscles ; but that it is, on the contrary, placed at a great distance 

 from that part, close to the lamellated organ, which Owen states 

 to be in relation with the oviduct and in the semilunar fissure 

 formed by that organ. 



7. That there is a distinct foramen in the pericardium, pre- 

 cisely similar to that which Owen^ has described and figured, 

 and which Valenciennes, consequently, erroneously denies. How- 

 ever, I am not certain that it communicates with the siphon ; and 

 I regret that the animal, being detached from the siphon, it was 

 not possible for us to determine whether the hypothesis which 

 Buckland** has proposed, in accordance with a drawing by Owen, 

 is quite accurate. It is a point which deserves to be studied 

 afresh. With respect to the foramen itself of the pericardium, it 

 cannot be doubted that it exists, and that it gives passage to an 

 artery. Requesting, Gentlemen, that you will insert this letter 

 in your estimable Journal, 



I have the honour to be, your obedient servant, 



W. Vrolik. 



XXIII. — Description of the Lurking Machete (Machserium sub- 

 ducens) from the northern coast of New Holland. By John 

 Richardson, M.D., F.R.S. &c.. Inspector of Naval Hospitals. 



[With a Plate.] 



The fish which forms the subject of this notice inhabits, in small 

 numbers, the various bays of Port Essington, where it lurks under 

 the mud in shallow waters. The aborigines name it '^ Ambeet- 

 unbeet.^^ Mr. Gilbert, assistant to Mr. Gould, brought home a 

 single specimen of the dried skin of one side, which was presented 



* Noiivelles Recherclies sur le Nautile flambe, 4to, 1839; Archives du 

 Mus6um, torn, ii. p. 279. 



t loc. cit. p. 20. I he. cit. p. 285. 



§ loc. cit. p. 27. II loc. cit. pi. 10. fig. \.w. 



^ loc. cit. p. 27. pi. 5. 0. ** Bridgewater Treatise, pi. 34. 



