72 MEMOIllS OF THE QUEENSLAND MUSEUM. 



1. belcheri Gray. 



Proc. Zool. Soc. London, 1847, p. 35 : Lundu River, Borneo (as Amyhioxus 

 belcheri) — Giinther, Voyi Alert, Zool., p. 32. 

 Figure : — Kirkaldy, Quart. Joum. Micr. Sci., xxxvii, p. 313, pi. 35, fig. 8. 

 Dimensions : — To about 50 miUim. 

 Range : — Prince of Wales Island, T.S. 



Genus 2— EPIGONICHTHYS Peters, Mon. Akad. BerHn, 1876, p. 325 [cultellus). 

 Syn. — Paramphioxus Haeckel 1893 ; Heteropleuron Kirkaldy 1895. 



2. cultellus Peters. 



Ibid. : Moreton Baj^, S.Q. — Giinther, ibid, (as Branchiostoma cuUellum). 

 Figure : — Kirkaldy, ibid., p. 316, pi. 34, fig. 2 (as Heteropleuron cuUellum). 

 Dimensions : — To about 55 millim. 

 Range : — Coast of Queensland from south to north ; Islands of Torres Strait. 



3. hedlejri Has well. 



Rec. Austr. Mus., vii, pt. 1, 9 March 1908, p. 33 (as Heteropleuron hedleyi). 

 Figure : — Haswell, ibid., text-fig. 1. 

 Dimensions : — Of type 28 miUim. 

 Range : — Murray Island. 



Genus 3— ASYMMETRON Andrews, Stud. Biol. Lab. John Hopkins Univ., v, 

 1893, p. 237 {lucayanum). 



4. caudatum WiUey, 



Quart. Journ. Micr. Sci., xxxix, 1896, p. 219 : Louisiade Arcliipelago — 

 Haswell, ibid, (as Heteropleuron-Asymmetron — lucayanum). 

 Figure : — WiUey, ibid., pi. 13. 

 Dimensions :■ — Of type 29-5 millim. 

 Range :■ — Murray Island. 



Note : — I think it advisable to follow Herdman (Cambridge Xat. Hist., vii, 

 p. 137) in keeping the eastern and western forms of Asymmetron separate, until more 

 is known about them, expecially the latter. 



Key to the Genera, 



a^ Preoral tentacles forming a continuous series ; infrarostral fold continuous with the right 

 metapleur only. 



b^. Gonad pouches developed on both epipleurs . . . . . . . . 1. Branchiostoma. 



6'. Gonad pouches developed on the right epipleur only . . . . . . 2. Epigonichthys. 



a^. Preoral tentacles not continuous ; infrarostral folds continuous with both nietapleui-s ; gonad 



pouches developed on the right epipleur only . . . . . . . . 3. Asymmetron. 



Keys to the Australian Species. 



1. Branchiostoma : — 



a^. Myotomes 63 to 65 ; gonad pouches 21 to 29 . . . . . . . . . • 1. belcheri. 



2. Epigonichthys : — 



a^. A notch between the rostral and dorsal folds. 



fti. Myotomes 70 to 78 ; gonad pouches 26 to 31 2. bassanus. 



b^. Myotomes .55 ; gonad pouches 17 to 22 . . . . . . - - - . 3. austraUs. 



a^. No notch between the rostral and dorsal folds ; myotomes 50 to 56 ; gonad pouches 17 to 20. 



c^ Preoral cirri 41 to 43 ; dorsal fold high 4. cultellus. 



c^. Preoral cirri 25 to 30 ; dorsal fold low 5. hedleyi. 



3. Asymmetron : — 



a^. Myotomes 60 . . . . . . . . . . . . • . • • • • . . 6. caudatum. 



