[133] NOTES ON ENTOZOA OF MARINE FISHES. 851 



The following details are taken from a living specimen slightly dis- 

 torted under the compressor : Length, 9.30 mm ; length of head and neck», 

 0.36 mm ; breadth of head, 0.32 mm ; length of bothria, 0.17 mm ; diameter 

 of neck, 0.10 mm ; diameter at contractile bulbs, 0.13 mm ; length of each 

 of first four segments, 0.02 mm ; breadth, 0.07 ; length of fifth segment, 

 0.04 mm ; sixth, 0.08 mm ; seventh, 0.12 ,um ; eighth, 0.10 mm ; ninth, 0.30 mm j 

 tenth, 0.44 mm ; eleventh, 0.60 mm ; twelfth, l. mm ; thirteenth, 1.25 mm ; 

 fourteenth, 1.8 mm ; fifteenth, 3 mm . The last *of these segments were 

 0.10, 0.14, and 0.2 mm broad, respectively. 



The length of the proboscides, estimated from specimens that had 

 been made transparent, so as to show the retracted proboscides, seems 

 to be from 0.5 to 0.6 mm . The longest everted proboscis measured 0.4 mm ; 

 diameter, excluding hooks, 0.011 to 0.016 mm ; including hooks, 0.019 to 

 0.025 n,m ; length of hooks, 0.007 to 0.008 mm ; breadth 0.003 mm ; length of 

 minute hooks at base of proboscides, 0.003 ; breadth, 0.001 mm ; length 

 of free proglottis, living, 4.4 mm ; breadth, 0.8 mm . 



In alcoholic specimens the bothria are invariably opposite and diver- 

 gent at the bases, so as to give to the head, when viewed laterally, margi- 

 nally as to body, a cordate or even reniform outline. The outline of the 

 head and neck together is like that of a hammer, in which the neck 

 represents the short thick handle. The head is only about half as thick 

 as it is wide, e. g. in an alcoholic specimen the breadth of head was 

 0.28 mm ; thickness, 0.14 mm ; in this specimen the length of a single both- 

 rium was 0.2 mm ; its breadth, 0.14 mm . In another specimen the head 

 was 0.32 mm broad and 0.14 mm thick. 



In the living worm the faces of the bothria are frequently directed 

 forward, and when viewed in this position their anterior edges are seen 

 to be separated by a moderately wide space. A pair of proboscides 

 emerges from the anterior edge of each bothrium. There is a slight 

 emargiuation on the anterior edge of each bothrium, and another shal- 

 low emargiuation on the posterior edge. A median line extending from 

 the shallow posterior notch to the front edge divides the bothrium 

 into two loculi. This latter feature is often lost, or at least much 

 obscured, in alcoholic specimens, in which the faces of the bothria are 

 deeply concave, the lips sometimes much iuflexed. 



Supplemental pits or otosacs. — These organs appear under low magni- 

 fying power as four round spots, lying one at each of the posterior angles 

 of the two bothria. When highly magnified, 250 to 300 diameters, 

 these spots are seen to be oval or conical pits, liued with minute ciliary 

 bristles, and about 0.025 mm in diameter. While examining one of these 

 pits with a magnifying power of about 300 diameters, the specimen was 

 subjected to a slightly increased pressure, when one of the pits was 

 observed to evert itself, changing from an ovai pit lined with ciliary 

 bristles to a blunt conical papillary elevation, which was covered with 

 erect bristles. In the alcoholic specimens some of these pits are everted 

 into low papillae. These remarkable pits are strongly suggestive of low 



