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THE OPHIURlDiE. 



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0. deprcssa there are really two tentacle scales at the inner pores. Often 

 the outer tentacle scale in 0. alba wholly covered the inner, Avhich then 

 could only be seen when the former was removed. It may be that they will 

 turn out to be the same species ; at present we dare not declare them to be so. 

 (0. dcpressa was taken near the Philippines^ in 500 fathoms.) 





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5. Ophiernus seminudus n. sp. 



Plato V. rigs. 10-13. 



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Diameter of disk, 20 mm.; width of arm close to disk, 3.5 mm. ; length 

 of arms, c. 5 times the diameter of the disk. Nine mouth papillae to each 

 side of the mouth angle ; the three outer ones are on the side mouth shields, 

 and on the first ventral plate; they must be considered as the papilla) of the 

 second mouth tentacle ; the middle one of these is especially large, rounded. 

 The rest of the papiha} are short, square, close set. At the apex of jaw, below 

 the teeth^ there are sometimes two or three small conical papillae, some- 

 times none. Some specimens have the inner mouth papilla) pointed and 

 longer than the outer ones; on the apex there also may be two rather large 

 conical papilla), or only one larger of the same form as the teeth; these 

 are five in number, long, pointed, lanceolate. Mouth shield more broad 

 than long, 1.5:1, with an obtuse angle within and outer edge straight, 

 the sides strongly produced, rounded. Side mouth shields rather broad, 



meeting within. 



First ventral plate hexagonal ; the rest of the ventral plates with inner 

 end truncated, outer edge curved ; lateral sides, both inner and outer part, 

 re-enteringly curved, the latter on account of the tentacle pores. They are 

 a little broader than long, all in mutual contact. Farther out the proximal 

 part of the ventral plates becomes narrow and rather long, stalk-like. 

 There is a rather distinct keel along the median line of the ventral plates. 

 The side arm-plates do not meet either below or above ; their outer edge is 

 not prominent. Dorsal plates twice as broad, as long, feebly keeled, with 

 inner edge a little concave, outer edge correspondingly rounded, lateral 

 sides straight; they are broadly in contact, the inner edge being incon- 

 siderably narrower than the outer edge. Far out on the arm they become 

 somewhat longer and narrower. The four to six first dorsal plates are more 

 or less rudimentary; the sides of the arms along these rudimentary plates are 



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