208 



BRITISH PALAEOZOIC PHYLLOCARIDA. 



" (2) The other view is that these animals were ecto-parasitic Phyllopods, 

 although they had not lost their power of free movement, yet had become special- 

 ised in the form of their body, which is flattened ventrally and only slightly 

 convex above, the whole animal being expanded horizontally, unlike most other 

 Phyllopods. This view might account for the two large round structures seen on 

 the ventral surface, situated one on either side of the body, and close to the 

 anterior margin of the shell. These might possibly represent a pair of ventral 

 suckers, such as are seen in the modern fish-lice ; these structures, whatever they 

 may be, are evidently enormously developed, and possess great muscles, which 

 produce prominent modifications of the dorsal shield, where they are attached. 

 The great labrum might possibly represent the suctorial tube of Argulus, under 

 cover of which are concealed the reduced mandibles, &c. 



" Some of the specimens show curious oblique scars on the coxaa of the legs, 

 which may indicate the points of attachment of spines or setse to enable the 

 parasite to stick to its fishy host." 



Note on Lebescontia occulta (see pages 203 — 205). 



Mr. John Smith, of Kilwinning, informs us (September 5th, 1899) that the 

 " Linn, Dairy," where he got the remains of Lebescontia occulta, is the " Linn 

 Spout, one mile south-west of Dairy," in the ' Catalogue of Western-Scottish 

 Fossils,' 1876, page 77 ; and he refers us to the paper on " The Upper Limestone 

 of North Ayrshire," by Mr. Robert Craig, of Beith, ' Trans. Geol. Soc. Glasgow,' 

 vol. viii, pp. 28 — 35. At page 32 the " Upper Linn Limestone " is described, the 

 section at Linn Spout being — 



1. Limestone 



2. Shale, very fossiliferous 



3. Limestone 



4. Shale, full of Posidonomya punctatel 



5. Limestone 

 G. Shale, indurated . 

 7. Coal, from 2 feet to 



49 10 

 The Lebescontia was collected by Mr. J. Smith in the shale, No. 4, abounding 

 with a fossil shell formerly known as Estheria punctatella, Jones. See the ' Trans. 

 Geol. Soc. Glasgow,' vol. ii (1867), p. 71, and vol. ix (1891), pp. 85—87. Hence 

 this shale has been known locally by the inaccurate name of the " Estheria-bed." 

 It is regarded by some as of estuarine origin. 



Feet. 

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