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Part III. — Eighteenth Annual Report 



Habitat. — On the grey skate, Raia batis, from the Firth of Forth, 

 the Firth of Clyde, and the Moray Firth, and on specimens of the same 

 fish brought to the Fish Market at Aberdeen. I found Trebius also on a 

 specimen of thornback, Raia davata, captured in the Firth of Clyde on 

 April 22nd, 1897. 



Genus Dinematura^ Latreille, 1829 (modified ^by Burmeister, 1831). 



Burmeister objected to the form of the word " Dinemoura " used by 

 Latreille, and changed it to Dinematura. This change in the form of 

 Latreille's name appears now to be generally accepted and used. 



Dinematura produda (Miiller). (PI. VI., figs. 27-31.) 



1785. Caligus produdus, Miiller, Entom., p. 132, PI. XXI., 

 fig. 3. 



1850. Dinemoura lamnm, Baird, op. cit., p. 286, PI. XXXV., 

 fig. 7. 



The Dinemoura {Dinematura) lamnoe, of Baird's monograph, now 

 identified as the Caligus jwodudus of Miiller, has been obtained by me 

 on one or two occasions during the past autumn on young porbeagle 

 sharks, Lamna cornubica, caught in the North Sea, and landed at the 

 Fish Market at Aberdeen. The larger specimens of Dinematura 

 measured fully four-fifths of an inch (20mm.) in length, exclusive of the 

 ovisacs, which were long and slender (fig. 27). One of the porbeagle 

 sharks, on which we obtained several specimens, was about three feet 

 three inches in length. 



The antenme of Dinematura produda (fig. 28) are armed with powerful 

 hooked terminal claws. The mandibles are elongated and very slender 

 (fig. 29). The anterior foot-jaws (fig. 30) are moderately stout, and each 

 terminates in a hook-like apex ; a short but stout and slightly curved 

 appendage also springs from the iuner aspect, and near the distal end of 

 the penultimate joint. The posterior foot-jaws are short and stout, and 

 somewhat rudimentary in structure. 



The first three pairs of thoracic feet are two-branched and somewhat 

 similar to those usually observed in the Caligidse, but the fourth pair are 

 large and foliaceous. The caudal segments are composed of broad quad- 

 rangular plates, the width of which is equal to about two-thirds of the 

 length ; their outer margin is nearly straight, but the inner is gently and 

 evenly convex ; the apex is subtruncate, and bears three small setae, while 

 a fourth seta springs from a notch near the distal end of the outer margin 

 (fig. 31). No males have been observed. 



The characters by which this species may be distinguished include, 

 amongst others, the form of the dorsal plates, the abruptly-hooked 

 antennse, the structure of the palpi and of the anterior foot-jaws, the form 

 of the fourth pair of thoracic feet, and of the caudal furca. 



One of the specimens obtained at the Fish Market at Aberdeen 

 measured three inches (75mm.) from the forehead to the ends of the long 

 ovigerous tubes. 



Genus JEchthrogaleus, Steenstrup and Lutken (1861). 

 Kdithrogaleus coleoptratus (Guerin). (PI. VI., fig. 32.) 



1817. Dinematura coleopttrata, Guerin, Icon. d. reg. Animal, 



vol. iii., PI. XXXV., fig. 6. 

 1850. Dinemoura alata, Baird,"op. cit., p. 285, PI. XXXIII., 



fig. 8. 



One or two specimens of this curious little species were found adhering 



