NEMERTEA 209 



C. lacteus* (Leidy) (Fig. 337). Body 2 m. or less long and 25 mm. 

 wide; extreme length up to 6.5 m. ; flesh color; proboscis white: very 

 common in the sand near low-water mark from Florida to Maine; breeds 

 from March to May in Long Island Sound and in July in Casco Bay. 



Order 3. HOPLONEMERTEA. (Metanemertini.) 



Body often very long and slender, but in many forms short and 

 thick; mouth in front of the brain, usually coinciding with the opening 

 of the proboscis; intestinal cascum present; proboscis provided with 

 stylets (Fig. 333) ; lateral nerve cords internal to the muscle layers of 

 the body wall; frontal sense organ present: 9 families and more than 

 200 species, which live in the sea, in fresh water, and on land; a few 

 species parasitic; development usually direct. 



Key to the families of Hoplonemertea here described: 



Oi Proboscis does not reach the hinder third of the body.l. Eaiplectonematidae 

 flo Proboscis reaches almost to the hinder end of body. 

 6i Four eyes usually present, forming a quadrangle. 

 c, Mostly hermaphroditic ; long, thin worms, some terrestrial. 



2. Prosorhochmidae 



^2 Unisexual worms, short and thick 4. Prostomatidae 



&2 Fyes numerous 3. Amphiporidae 



Family 1. EMPLECTONEMATIDAE. 



Body very long and thin; proboscis short 

 and thick and with a single main stylet of 

 variable form; usually with very small eyes: 5 

 genera and about 25 species. 



1. Emplegtonema Stimpson. Mouth and 

 proboscis openings coincide ; usually with many 

 eyes, never only four; accessory stylets pres- 

 ent: 16 species. 



E. gracile (Johnston) (Fig. 338). Head 



end wider than body and with 20 to 30 eyes on 



each side; length about 20 cm.; breadth 1.5 



mm.; color green; stylets slender and curved 



, ,/ , * -P .„ , ,, f Fig. S38—Emplecto- 



at the end : very common on Facinc coast north f nema gracUe (Coe) . 



of San Francisco, in shallow water; Europe. 



2. Carcinonemertesj Coe. Body long and slender, cylindrical, 

 usually not coiled; mouth and proboscis coincide, the latter being 



* See "On the Anatomy of a Species of Nemertean (Cerebratulus lacteus Ver- 

 rill)," by W. R. Coe, Trans. Conn. Acad., Vol. 9, p. 479, 1895. "The Habits and 

 Early Development of Cerebratulus lacteus," by C. B. Wilson, Quart. Jour. Micros. 

 Sci., Vol. 43, 1900. 



t See "Nemertean Parasites of Crabs," by W. R. Coe, Am. Nat, Vol. 36, p. 431, 

 1902. 



