PARASITIC ROUNDWORMS 3,3 



14 (9) Male with bell-shaped bursa encircling posterior end; no sunrwrlinu 



ribs in bursa. No buccal capsule. 



Family Dioctopiiymidae Raillici 1015. 



Mouth surrounded by one or two circles of papillae, 6. ,2. or ,8 in number. Ks.,phi«u. 

 very long, without bulb. One ovary; vagina very lonL-. Vulva near anleriur n.d anu^ 

 terminal in female. One long spicule. Eggs with very Lhick pitted shells Lar«c worms 

 in some genera armed with spines near anterior end. ' 



Only genus parasitic in North American aquatic hosts. 



Dioctopliymc Collel-.Meygret i.Ho:. 



Anterior end unarmed; mouth surrounded by six papillae. 



Only species known Dioctophytnc rcualc (Coc^.q) i-jSi. 



Color blood red; six circumoral papillae and 150 al..ng latrral lines 

 Male up to 40 cm. long, 4 to G mm. broad. Anus terminal, surmundcd 

 by circular bursa without ribs. Spicule 5 to 6 mm. long. Female up 

 to I m. long, and 12 mm. broad. Anus crescentic, terminal. Sex p.irc 

 only 50 to 70 mm. from anterior tip. Uterus single. Eggs oval- shell 

 brown, very thick, deeply pitted except at poles. 



In pelvis of kidney of seal, otter, dog. wolf, etc. Rare in man 

 Reported from mink and dog in Pennsvlvania bv Leidy. Found in 

 dogs at Chicago, Illinois. Intermediate host probably a fish. 



The giant among nematodes; a dangerous and little known para>itc 



Another form which may belong here was collected in Florida by 



Wyman from the water-turkey or snake-bird and described as -nearly 



Fir Srfi ninrfnt,hv,„P ^f ^^t i(ientica.l With Eustrongylus papillosus lYxv^lnK \n Plolus ankiniia 



renal^. ' Ante^Sr^nd of ^JP^, Brazil." The species last mentioned was included in the genus 



female. X3. (After Riley ^ystnchis by Mohn, but as the identihcation of Wvman was not final 



and Chandler.) it is impossible to enter Uystrichis papillosus definitely among North 



American species. 



15 (8) Bursa absent or weakly developed in male. True buccal capsule 



wanting 16 



Compare the discussion under 9 (14) in this key. The caudal alae, often but incorrectly 

 called a bursa, when present consist of long, narrow wings not projecting conspicuously from 

 the body but parallel to it and not supported by radiating ribs, but having at most a scries 

 of canals at right angles to the body. 



16(51) Very long, slender forms, with or without lips 17 



17 (26) Esophagus slender, simple, no bulb. 



Superfamily Filarioidea Weinland 1858 . . 18 



The anterior end is usually plain and no lips are present though in some cases a few minute 

 oral papillae can be recognized. The esophagus has only a single region. The posterior end 

 of the male is rolled into a close spiral of two or more coils. The vulva lies far anteriati and 

 the forms are usually ovoviviparous. The group as now conceived is much m»tre sharply lim- 

 ited than formerly. 



18 (19) Anus wanting in adult; vulva lacking in adult female. 



Family Dracunculidae Lcipcr iqi.:. 



The famous guinea-worm of man known since ancient times belongs in this group. After 

 impregnation the sexual pore disappears and no trace of it has been found in the adult. I he 

 females grow to a relatively enormous size coincident with the development of great numliers 

 of minute embryos which fill the uterus. The larvae develop in aquatic organisms, prob- 

 ably Copepoda, Ostracoda, etc. 



Only North American genus 7r///// wmvmj Diesing 186 1. 



Mouth surrounded by four low papillae. No buccal cax-ity. Esophagus funnel-shaped at 

 origin. One esophageal gland with large nucleus. Polymyarian. I'terus broad, traversing 

 entire body, with short ovary at each end. Embryos develop in uterus. No anus, vulva, or 



