A. jG Verrill — Marine Nenierttans of New England, etc. 385 



fossae or grooves on the sides of the head. They are probably 

 olfactory organs. Two large lateral nerves run back from the lower 

 cephalic ganglions; often there is also a smaller median dorsal nerve 

 trunk, and in many there is a continuous nervous plexus between the 

 muscular layers of the body-wall. 



Vascular system closed ; a main longitudinal vessel runs along- 

 each side and usually a median dorsal one is situated above the 

 intestine; the blood is usually colorless, rarely red. 



A paired nephridial system, consisting of ducts and tubules vari- 

 ously arranged, is usually present in the oesophageal region. 



The sexes are almost always separate and nearly all the species 

 are oviparous. Reproductive organs are very simple and similar 

 in both sexes, consisting of simple saccular ovaries or spermaries, 

 situated along the sides of the body, usually between the lateral 

 saccules of the intestine. External genital openings are mere pores 

 in the body-wall. 



Development is usually direct, but sometimes with a metamorphosis 

 through a Pilidium, or free swimming larval form, very peculiar 

 in structure. (Plate xxxix, figures 1 to 6). 



Order I, ENOPLA. 



Enopla M. Schultz; Mcintosh, Brit. Annelids, Part I, Nemerteans, pp. 36, 43, 134. 

 Ilojilonemerimillubriicht] Cams, Fauna MediterraneEe, p. 163, 1884. 

 Hoplonemertea Hubrecht; Voy. Challenger, vol. xix, p. 15. 



Proboscis divided into three distinct regions (Plate xxxix, figures 

 7, 8, 9) ; the first is evertible and tubular ; the middle region (wood- 

 cut 1), is furnished with a hollow miiscular bulb and a complex 

 armature, consisting of a central calcai-eous st^det (o), or a toothed 

 plate, usually accompanied by two or more lateral chambers con- 

 taining small, pin-like, free spines or stylets (figures 7, "la, and wood- 

 cut 1, r>, I)'), The central cavity of the bulb and the lateral stylifer- 

 ous chambers communicate with the anterior evertible chamber of 

 the proboscis by means of ducts. Proboscis-pore is either terminal, 

 at the end of the snout, or subventral. 



Fig. 1. Armature of proboscis of Amphiporus ladifloreus; A, muscular bulb; B, 

 its cavity; c, central stylet; d, d', lateral stylet-sacs: e, duct of d; h, muscular 

 b^nd, (after Mcintosh). 



