188 
20. 
22. 
oy 
23) 
24. 
2 
20. 
275 
28. 
20. 
46. 
47. 
48. 
Papers from the Marine Biological Laboratory at Tortugas. 
Pedibothrium brevispine gen. et sp. nov., from Ginglimostoma cirratum. 
21. Single hooks, different views; actual length 0.068 mm, 
Free, ripe segment, balsam; actual length 2.8 mm. 
PLATE 4. 
Pedibothrium brevispine, continued, from Ginglimostoma cirratum. 
Pair of hooks; actual length 0.064 mm. 
Head, balsam; maximum diameter 0.21 mm. 
. Free, ripe segment with cirrus exserted; actual length 2.8 mm. 
Acanthobothrium brevissime sp. nov., from Dasyatis say. 
Strobile, balsam; actual length 1.43 mm. The enlargement at the base of the 
neck is probably a contraction character. 
Head, balsam; length of head 0.25 mm. 
Single hook. 
Pair of hooks, prongs broken. 
Actual length in figs. 28 and 20, 0.05 mm. 
IPAOINND, Ep 
Rhynchobothrium simile sp. nov., from Ginglimostoma cirratum. 
. Head, neck and anterior part of strobile; lateral view of the head; actual diameter 
of neck behind head 0.6 mm. 
. Head, showing margins of bothria; diameter of neck behind head 0.65 mm. 
. Proboscis, near base; diameter, exclusive of hooks, 0.19 mm. ) 
. Proboscis, near base, showing side opposite to that shown in figure 32; diameter, 
exclusive of hooks, 0.17 mm. 
. Proboscis 0.8 mm. from base; diameter, exclusive of hooks, 0.17 mm. 
36. Two types of hooks shown in fig. 34, more enlarged; lengths 0.16 and 0.17 mm. 
. Last segment, in glycerin; length 2 mm. 
PEATE (6: 
Rhynchobothrium simile sp. nov., continued. 
. Base of proboscis; diameter, exclusive of hooks, 0.17 mm. 
Rhynchobothrium lineatum sp. nov., from Ginglimostoma cirratum. 
. Head and neck, balsam; length of head and neck 3.5 mm. 
. Proboscis at base; diameter, exclusive of hooks, 0.05 mm. Partly diagrammatic. 
. Proboscis, middle; diameter, exclusive of hooks, 0.04 mm. 
. Proboscis, near apex; diameter, exclusive of hooks, 0.04 mm. 
. Segment toward posterior end of strobile; length 1 mm. 
Rhynchobothrium curtum sp. nov., from Galeocerdo tigrinus. 
. Head, neck, and anterior part of strobile, alcoholic, showing marginal view of 
bothrium; length of head 0.20 mm. 
. Lateral view of bothrium, and anterior end of strobile, alcoholic; length of both- 
rium 0.19 mm. : 
Same view of another specimen mounted in balsam; length of bothrium 0.19 mm. 
Last segments of strobile mounted in balsam; breadth of last segment 0.33 mm. 
PrATE a7. 
Rhynchobothrium exile sp. nov., from Galeocerdo tigrinus. 
ae neck sketched from alcoholic specimens; diameter of neck, anterior, 
0.28 mm. 
