NOTE on the CEPHALOCHORDA in the AUSTRALIAN 



MUSEUM. 



By Professor W. A. Haswell, M.A., D.Sc, P.R.S., Trustee. 



(Figure 1.). 



Seven specimens of Amphioxns obtained in the dredge by 

 Messrs. C. Hedley and A. R. McCulloch, at a depth of 5 to 8 

 fathoms at Murray Island, represent two of the sections into 

 which the genus Brancliiostoma may be divided. 



Heteropleuron (Assmmetron) lucayanum, Andrews. 



The discovery of this species, originally found in the "West 

 Indies, in such a distant locality as Torres Strait, would appear 

 somewhat remarkable (though by no means without parallel) 

 were it not that the species of Asymmetrou, obtained by Willey, 

 in the Louisiade Archipelago, and named by that author 

 A. caudatum, is now looked upon by him as not distinct specifi- 

 cally from the original type form of the sub genus. As Murray 

 Island is only about five or six hundred miles west of the 

 Louisiades, there are many resemblances between the respective 

 faunas, and it is not surprising to find a species of Amphioxus 

 common to both. 



Heteropleuron hedleyi, sp. nov. 



The three specimens are of the same length — 2*8 cm. In each 

 of the two complete specimens there are fifty-four myotomes and 

 nineteen gonads. In the third specimen several myotomes and 

 gonads have been destroyed. 



The opening of the oral hood is opposite the interval between 

 the fifth and sixth segments ; the atriopore opposite the thirty- 

 third, the anus opposite the forty-fourth, and behind the anus 

 there are either ten or eleven myotomes. The myotome formula 

 is 33.11.10 or 11. 



