456 



MR. G. S. BRADY'S MONOGRAPH OF 



Hab. This species occui's from low-water mark to the greatest depths that have yet been dredged in the 

 British seas. Shetland, Frith of Clyde, Skye, Youghal, Plymouth {Rev. A. M. Norman) ; Aber- 

 deenshire coast [Mr. Dawson) ; Hebrides and Channel Islands {Mr. J. G. Jeffreys) ; Devonshire 

 {Mr. C. Spence Bate) ; Cumbrae, Macduff, Peterhead, and Ormeshead, and at low water-mark, Isle 

 of Man {Mr. D. Robertson) ; Northumberland and Durham coasts (30-46 fathoms); Birterbuy Bay 

 and in oyster-ooze from Stranraer (G. /S. i?.) ; Norfolk coast {Mr. D. O. Drewett) ; and in shell-sand 

 from the Girdler Sand, Margate, and Donegal {Mr. E. C. Davison) . 



One of tlie most widely distributed, and, in most localities, one of the more abundant 

 species. It is readily distinguished from all others by its peculiarly flexuous outline. 



Genus 14. Paradoxostoma, Pisclier. 



Shell thin and fragile, smooth, shining, and having no definite structure; valves sub- 

 equal, mostly much higher behind than in front, usually elongate-ovate. Lucid spots as 

 in the preceding genus. Hinge-joint simple. Ventral margins emarginate in front, so 

 that when the valves are closed there is still an elongated orifice, through which the 

 suctorial mouth can be protruded. Upper antenna) exceedingly slender, 6-jointed, and 

 bearing short setae; lower shorter and more robust, 5-jointed; flagellum large and 

 almost as thick as the antenna itself. Poison-glands large and mostly lobulated. 

 Mouth suctorial, Labrum and labium forming together a large and stout subcorneal 

 process projecting downwards, and terminating in a disk with elevated margins, in the 

 middle of which the orifice of the mouth is situated. Mandibles very slender, protrac- 

 tile, styliform, subulate at the apex ; palp very slender and elongated, indistinctly jointed, 

 and without a branchial appendage. Terminal lobes of the first pair of jaws very 

 narrow ; branchial plate elongate-ovate, and bearing at the base two deflexed setae. 

 Feet short and robust, last joint elongated, terminal claw very short and curved ; basal 

 joint of the first pair armed at the apex with a single strong spine. Postabdominal lobes 

 bearing two short hairs. One eye. 



The peculiar characters of the mouth in this genus were first noticed by Pischer, and 

 by him were justly made the ground of separation from other Cytheridse* ; these observa- 

 tions were made on species found in Madeira. Herr G. O. Sars, however, has described 

 with much more minuteness and accuracy, in his ' Oversigt af Norges marine Ostracoder,' 

 to which reference has so frequently been made in these pages, the anatomical characters 

 of the genus. The suctorial mouth and the stylet-shaped mandible are very extra- 

 ordinary, and show an interesting approximation to the structure of the mouth-organs 

 in the parasitic Copepoda. It is not likely, liowever, that the members of this genus are 

 in any sense Epizoa ; they have never been taken in situations at all dififerent from those 

 frequented by other Ostracoda, being constantly met with on the fronds of algee in 

 littoral situations, or in the mud and ooze of considerable depths of water. Indeed we 

 cannot doubt that the piercing and suctorial apparatus with which they are armed is 

 used, not for the abstraction of the vital juices of any large animal, but simply as a 

 means of appropriating the nourishment found in the monads and other minute animal 

 prey on which the Crustacea appear mostly to subsist. Sars, indeed, conjectures that it 



* Abhandl. d. kgl. bayerischen Akademie d. Wissenschaften, Bd. vii. 



