NEMEKTEA ENOPLA 



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13. The testes consist of many small peripheral sacs that open 

 into a large V-shaped sac as known in the Drepanophoridae 

 only, and representing probahly a more primitive stage 

 than that of most Drepanophorus species. 



Every organ of Siboganemertes is either more primitive than 

 in the other Eeptantia or quite differently developed (rhyncho- 

 coelomic diverticula, digestive system, nephridia, dorsal 

 blood-vessel). We must include it in the well-defined group 

 of Eeptantia as given by Brink m a n n . On the other hand 

 we cannot include this genus in his family Drepanophoridae, 

 nor in the Uniporidae or any other family of the Siboga material. 

 The real relationship between the known Drepanophoridae 

 and Siboganemertes we can only indicate by dividing the 

 tribus Eeptantia (Brinkmann) into two subtribus, the Archi- 

 reptantia and the Eureptantia, of which the first contains the 

 family Siboganemertidae and the other the different groups of 

 Drepanophoridae as yet known. 



The diagnoses of the different systematic divisions of Enopla 

 are as follows : 



Sub-classis Enopla (Max Schultze). 



The body-wall consists of a one-layered epithelium, a 

 basement membrane, a circular muscle-layer, and an inner 

 longitudinal muscle-coat. The nervous system is embedded 

 in the body parenchyma. Cerebral organs, where present, 

 separated from the brain. Proboscidian and digestive system 

 show a tendency to acquire a common mouth. Blood- 

 vascular system without lacunae. 



Ordo I. Bdellomorpha (Yerrill). 



Parasitic Nemerteans with a sucker. The proboscis is in- 

 serted in the wall of the digestive system ; without armature. 

 Digestive tract a more or less winding tube without diverti- 

 cula and blind-gut. Blood-vessels highly branched. 



Ordo II. Hoplonemertini (Hubrecht). 



Proboscis armed. Digestive system with blind-gut and 

 paired diverticula ; straight. Vascular system without tree- 



