BY T HARVEY JOHNSTON AND B. BUCKLAND TAYLOR. 39 
KEY TO GENERA OF CHAETOGNATHA. 
From Ritter-Zahony (1911, p. 44). 
IE MUrAnAVerse eIMUSCless OM OGY sere idole feleisi lo loll oiole ele) @ ol <=) ele) +1) «11 «1° 2 
IN@itransverse muscles) OmmnOdy, <tc \)s)1 ie) lersi=/a)s.ce 1 se «21s se) 010) =)0\ ele) oi 4 
2. Medium sized species, with 1 or 2 rows of numerous teeth 
on each side, and an extensive pair of fins extending 
WOE OMY SAMRAT ce apt etaiiee ols ais) aia -teicke ieke [1 shvini='a) Ves <i) eins 3 
Small compact species with 1 or 2 rows of small teeth, 
a pair of fins on the tail, and may have a second 
smell Toei GE UNS GN Wa DOC Nagasan dds eoobocdsocsouee Spadella 
3. Two rows of teeth on each side, transverse muscles in 
ANGEMOL GhIrGe OL ball ees sors) leuevererers 3218 6/0 steiciens!on ae Heterokrohnia 
One row of teeth on each side, small transverse 
ANNTERGLOSE OLIN LAME 5 coy=)'a fa) ele cvataie nbs) ayedohe eras ale ersietsVoreseis Sel s\ehar« Eukrohnia 
4. One row of slender converging teeth on each side, one 
Palrmotwla Geral fins iio, a sells jac cecre cn -vacsves she tee aucrerers w,-ve10 Se Krohnitia 
MwOsrows) OL conical teethron) each Side... circle eles os swe elan a 5 
5. Two pairs of lateral fins, sometimes fused together.......... Sagitta 
One pair of lateral fins on the tail, as the continuation 
OLmauavoluminous) -collaretteag sa sins ae 0s ors aieiersls ele Pterosagitta 
KEY TO SPECIES OF SAGITTA 
recorded from Australian waters. 
Ibe Bodys transparent yands flaccid! (7 e)..1-.6)<101 2-12) steels 0121s) -) steel shcie) 0 fers 3 
OF, lakerihve sth Guava l Cap oE KC 6 agm enon oO rOe on ab Od oT OAC Oe aD COMOmCeD Or 6 
tae NOCKCONSULIC HON VeLY, MaLKeG series ceyae aeteieie faleieiciererectereretsieiel 4 
Neckmconstrction note marked. n+. e- tects sets cisco sre aieliel)s ee 5 
4. Anterior fin extends in front of ganglion................ australis 
Anterior findoes nob meachivamelion ys ces seis =e ceieie «sole ele enflata 
ae COMaretter pleseMureaiersarcst sos ior aoiateye atet s Sereyeateraic race ste oeehen oles pulchra 
Collarettem absentee ste aces «jac cls aso ceremioandiene ners aaueerras minima 
Ome Veoth serrated sys: .s asic %s cle os eee haters chaps arse berets: gists. lek serratodentata 
Meothin noth a SEELate” veloc s:scvsateiers eaiovonexses erste tlelnises eta esicds arora u 
Ue bosterionceethimorerunan: 20). creche aver sets s cree sic) Ss) = eeresys) es ae bedoti 
iRosteriors teethw fewer sthani 20 )sc sess yerstste ree suet sl acy -ssyer-1 <'t stegete) ve 8 
8. Collarette extends over whole head and to anterior fin...... regularis 
Collarette extends from behind head to anterior fin.......... robusta, 
Collarettog veryusmialllprs sasci marti sree cielo Saree 00s) ele sialic cites etsy sae 9 
9. Posterior fin extends to seminal vesicles.................. bipunctata 
Posterior fin does not extend to seminal vesicles................ 10 
10. Anterior fin less than 15% total length.../................ tenuis 
Anterior fin more than 15% total length.............. neglecta 
