13 (12) Carapace with 2 or more supraorbital spines on each side; third maxilliped with 



exopod Spirontocaris A 



A (13) Dorsal teeth extending to, or beyond, posterior third of carapace B 



A (13) Dorsal teeth falling short of posterior third of carapace S. phippsii 



Figure 24. — Spirontocaris phippsii: carapace, lateral view. 



B (A ) Ventral margin of rostrum with 4 to 6 teeth; tip ascending to a well-defined single 



point S. liljeborgii 



1 I 



Figure 25. — Spirontocciris lilljeborgii; carapace, lateral view. 



B (A ) Ventral margin of rostrum with about 2 (occasionally 3) large teeth and variable 

 number of smaller ones (none to many); tip single or double and often almost 

 equalled or surpassed by distalmost ventral tooth S. spinas 



Figure 26. — Spirontocaris spinas: carapace, lateral view; A, B, two examples of variation in rostral tooth pattern. 



10 



