198 GRIFFIN. 



proved a very heterogeneous assemblage, since under this term 

 forms were included that differ as widely from each other as 

 they do from the Enopla {e.g., Carinclla, CcpJialothrix, Ccrcbra- 

 tuhis). These faults were partially removed by Hubrecht ('79) 

 in the following system : 



1. PaL.'EONEMERTINI. 



No deep lateral fissure on the side of the head. No stylet in 

 the proboscis. Mouth behind ganglia. 



Carincila, Ccplialotlirix, 



Polia, Valcncinia. 



2. SCHIZONEMERTINI. 



A deep longitudinal lateral fissure on each side of the head, 

 from the bottom of which a ciliated duct leads into the posterior 

 lobe of the ganglion. Lateral nerves between the longitudinal 

 and inner circular muscular coat of the body wall. Nervous 

 tissue deeply tinged with haemoglobin. Mouth behind the 

 ganglia. 



Linens, Borlasia, 



Ccrcbratiihis, Langia. 



3. HOPLONEMERTINI. 



One or more stylets in the proboscis. Mouth generally sit- 

 uated before the ganglia. Lateral nerves inside the muscular 

 coats of the body -wall. No deep longitudinal fissures on each 

 side of the head. 



DrcpanopJwriis, AinpJiiporns, 



Tetrastcinnia, ProsorhocJinms, 



Oerstedia, Ncincrtcs. 



The above system, the result of a deeper study of the inner 

 organization of these worms, marked an important advance in 

 taxonomy. A single character (presence or absence of stylets) 

 is here no longer taken as the basis of division, but a group of 

 characters ; and, moreover, the importance of the number and 



