7 (8) 
8 (7) 
9(10) 
10 (9) 
11 (12) 
12(11) 
13(14) 
14(13) 
15 (4) 
16 (17) 
17 (16) 
18(19) 
19(18) 
20(23) 
21 (22) 
22 (21) 
23 (20) 
24 (1) 
25 (26) 
26 (25) 
254 
Proboscis bearing three circles of twelve hooks each................... 
PPE RE A CER es Oe OANA Be J Gracilisentis gracilisentis. 
Proboscis bearing three circles of less than twelve hooks each......... 9 
Hight hooks in each circle............... Octospinifer macilentus, Nn. sp. 
Six hooks in; each circle sai): isoscch ests speteredepaie = el alats bas w chale 8 errs 11 
Hooks of basal circle over 40 » long. Body wall about 80 uw thick....... 
Da tetas oheiaiaans otc malate nti tentom Reliab iahs Neoechinorhynchus crassus, n. sp. 
Hooks of basal circle less than 40 w long. ........ cece eee ee eee eee 13 
Body very long, approximately cylindrical. Embryos within body of 
gravid female usually over 48 uw long. .Neoechinorhynchus cylindratus. 
Body tapering conspicuously from anterior region toward the posterior 
extremity. Embryos within body of gravid female less than 45 uw 
NONE: fe nssheuts sehen eis Re rekon Oe Peleraiohe meee racer Neoechinorhynchus tenellus. 
Proboscis variable in shape but never globular; always bearing more 
than three circles’ Of NOOMKS) <j. scmsecrs = ein iteleinielese he ne sree y- eels eee 16 
Proboscis long, approximately cylindrical. Body of almost same diame- 
ter throughout. Cement gland a single syncytial mass. Proboscis 
receptacle a single walled sac. Giant nuclei of subcuticula plainly 
observable in stained specimens......... Tanaorhamphus longirostris. 
Proboscis long or approximately ovoid. Male bearing several separate 
and distinct cement-glands, variously grouped. Proboscis receptacle 
a double-walled sac. Nuclei of subcuticula small and numerous or 
FITS VY STAT GLC ie ose Sian dehy ate Pekalel otek = a lediorn acer ol hed ancy ep eyalny ola? =\ car aiel al are ean 
Brain located at base of proboscis-receptacle. Retinacula coming off 
from posterior end of receptacle. In intestine of amphibian.......... 
Acanthocephalus ranae. 
Brain located some distance anterior to the posterior end of proboscis- 
receptacle. Retinacula given off from sides of receptacle........... 20 
Anterior region of body slightly inflated and larger than posterior por- 
tion, which tapers gradually toward posterior extremity........... 21 
Proboscis bearing sixteen longitudinal rows of hooks. Embryos within 
body of gravid female 115 to 165 » long, the middle membrane drawn 
out into polar prolongations more than twice as long as wide........ 
sb eels asa eral TaU aac Ea tanta fe ote recins TersagattvPaNe ay ose Echinorhynchus salvelini. 
Proboscis bearing twelve longitudinal rows of hooks. Embryos within 
body of gravid female 51 to 91 mw long, the polar prolongations of 
middle membrane usually not much longer than wide............... 
SNe i Porte eit ee er caster uth tn Echinorhynchus coregoni Linkins, n. sp. 
Body tapering gradually from anterior region posteriorly. Lemnisci 
long. Embryos 80 to 110 w long.......... Echinorhynchus thecatus. 
Body proper provided with cuticular spines in anterior region. Pro- 
boscis long, cylindrical. Parasitic in intestine of fish.............. 25 
Proboscis armed with twenty-two to twenty-four longitudinal rows of 
MOGES | Ate bake eee elise hae ceiote Se Maemetata a aete Rhadinorhynchus ornatus. 
