PARASITES OE FISHES OF THE WOODS HOLE REGION. 
417 
Analytical hey to the genera of Cestorlcs mentioned in this report. 
3. Scolex spherical or subspherical with cup-like bothria , 
2. Scolex oi various shapes, but unlike 1 
, /Scolex simple 
"'/Scolex with retractile appendages in front 
. (Scolex mushroom shape without bothria 
4 '/Scolex provided with bothria 
- (Bothria two - - 
1 ' (Bothria four 
„ (Bothria united into a discoidal or subglobular mass 
“' /Bothria distinct 
» (Scolex discoidal 
'■/Scolex subglobular with subglobular myzorhynchus 
„ (Bothria without auxiliary suckers 
a 'i Bothria with auxiliary suckers 
... (Bothria with costte 
1 '/Bothria without costte 
(Scolex with myzorhynchus 
xi ' (Scolex without distinct myzorhynchus 
(Bothria in pairs, fan shape, with frilled or lobed borders 
-jo (Two auxiliary suckers on each botbrium 
la '/One auxiliary sucker on eachbothrium 
, , (Auxiliary suckers relatively large, formed from anterior part of botbrium. . . 
i4 ' (Auxiliary suckers small, circular 
(Auxiliary suckers entire, scolex with terminal haustellum 
10 ' (Auxiliary suckers horseshoe shape, anterior ends of bothria partly retractile 
... (Bothria in pairs 
'(Bothria cruciform 
,o /Bothria slender pedicelled, with crenulate borders 
10 ’ (Bothria short pedicelled, border not crenulate 
(Bothria armed with hooks 
’■ (Bothria provided with retractile spiny proboscides 
(Hooks inconspicuous, of densely fibrous structure 
“’"(Hooks chitinous, structureless 
(Bothria without auxiliary suckers 
■“' /Bothria with auxiliary suckers, anterior to hooks 
9 o (Scolex flattened, bothria in pairs, hooks in pairs united by a chitinous bar. . . 
"'/Bothria cruciform 
24 (Hooks with two prongs each, bothria costate 
Z4 'i Hooks with three prongs each, bothria loculate at posterior end 
9 c (Bothria two 
/Bothria four 
nr- (Bothria each with an auxiliary pit 
(Bothria without an auxiliary pit 
.„ (Bothria lateral 
“' /Bothria terminal 
3. 
4. 
Txnia. 
Paratxnia. 
Discocephalmn. 
5. 
. . . Dibotliriuiii . 
6 . 
Lecariicephalum. 
Tylocephalum. 
9. 
19. 
10. 
13. 
11. 
12. 
Echcneibothrium. 
Rhincbothrium. 
Spongiobothrium. 
Anthobotlirium. 
1 Orygmatobothrium. 
11. 
15. 
16. 
Monorygma. 
Calyptrobothrium. 
' 17. 
18. 
New Ccstodefrom Tile-fish. 
Phyllobothrium . 
A nthocrphalum. 
Crossobothrium . 
20. 
25. 
Thysanocephalum. 
21. 
! ! ! ” ” ” ” ” ! ! 1 ! ! ! ! 7 ! 23! 
Onchobothrium. 
Calliobothrium. 
Platybothrium. 
24. 
Acanthobothrium. 
Phoreiobothrimn. 
Rhynchobothrium. 
26. 
Otobothrium. 
27. 
Tdrarkynchus. 
Synbdtkrmm. 
Analytical key to the Dixtoma nie.ntioned in . this report. 
Body unarmed 1. 
Body armed with spines 1 6. 
. (With a more or less retractile caudal appendage Table I. 
’"/Without a retractile caudal appendage. 2. 
„ (Sexes separate. See Pistomum ( Kblllkcria ) sp. from cysts in Scornbcromorus maculatus. 
'/Sexes united, hermaphroditic 3. 
o (Head provided with lobes (Banodcra) . See Distomum cmricidatuvi. 
1 Head without lobes 1. 
. (Forks of intestine with lateral folds or branches Table IV. 
4, | Forks of intestine simple 5. 
- /(Esophagus none or very short Table II. 
' ((Esophagus distinct Table III. 
(Mouth armed with spines Table V. 
(Forks of intestine simple, testes normally two Table VI. 
7.' Each fork with an anteriorly directed branch from near base of oesophagus, testes numerous [Plearchc] 
Distomum polyorchis. 
’The species referred in early papers to Orygmatobothrium angustwm has been placed in this paper in the genus 
Crossobothrium. 
F. C. B. 1899—27 
