THE NEMERTINI 



171 



The proboscis is as long as the body. The rhynchocoel extending into 

 the hinder third, and even to the end of the body. 



FAMILY 3. PROSORHOCMIDAE, Biirger. With four eyes, cerebral 

 organs are rudimentary. Cephalic gland large. Mouth and rhynchocoel 

 coincident. Usually hermaphrodite. Prosorhocmus, Keferst. ; head 

 notched anteriorly (Fig. IX.). Prosadenoporus, Burg. ; Geonemertes, Semper, 

 is terrestrial (10). FAMILY 4. AMPHIPORIDAE, M'Intosh. Eyes numerous. 

 Cerebral organ large ; the intestinal pouches 

 are branched, and the gonads do not alter- 

 nate regularly with them. The anterior 

 caecum has long lateral diverticula. Amphi- 

 porus, Ehrenb. ; Drepanophorus, Hubr. ; with 

 unique armature to proboscis ; the rhyncho- 

 coel is provided with inetameric diverticula. 

 Zygonemertes, Hontg. ; Proneurotes, Montg. 

 FAMILY 5. TETRASTEMMATIDAE, Hubr. 

 Small, flattish worms, with four eyes in a 

 rectangle. Tetrastemma, Ehr. ; several fluvi- 

 atile as well as marine species. SticJio- 

 stemma, Montgomery ; fresh water. Oerstedia, 

 Quatref. FAMILY 6. NECTONEMERTIDAE, 

 Verrill. Short, broad body, with " cirri " ; 

 tail with horizontal fin ; apparently without 

 stylets on the proboscis (see 41). Necto- 

 nemertes, Verr., 636 to 1735 fms. Hyalo- 

 nemertes, Verr., 826 to 1641 fms. Atlantic. 

 FAMILY 7. PELAGONEMERTIDAE, Moseley. 

 Pelagic, deep sea, transparent, leaf-like body ; 

 proboscis unarmed ; no dorsal blood-vessel. 

 Pelagonemertes, Moseley ; P. rollestoni, M. ; 

 South Sea, 1800 fms. (Fig. XL). P. moseleyi, 

 Biirg.; S.E.Japan, 755 fms. Pterosoma, Lesson 

 (see 20). FAMILY 8. MALACOBDELLIDAE, 

 v. Kennel. Parasitic ; short, compact body, 

 with a posterior, ventral, glandular "sucker." 

 The intestine is undulating, without pouches 

 or anterior caecum, the proboscis is unarmed. 

 Malacobdella, Blv. ; without eyes or cerebral 

 organs. The proboscis opens into the fore- 

 gut. M. grossa, 0. F. M. (Fig. XIII.) ; in the mantle chamber of various 

 lamellibranch molluscs (see 24). 



BRANCH B. TRIMYARIA. Anoplous Nemertines in which a secondary 

 coat of longitudinal muscles is developed outside the circular coat (Fig. X.). 



ORDER 4. Heteronemertini, Biirger ( = Schizonemertini, Hubr. 

 + Eu2wliidae, Hubr.). 



The lateral nerve stems lie between this secondary coat and the 

 circular coat. The mouth is behind the brain ; there is no anterior 

 enteric caecum. 



FIG. IX. 



Prosorhocmus claparedii, Kefer- 

 stein. A viviparous Nemertine, 

 (After M'Intosh, from 



