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CLASS CKUSTACEA. 

 ORDER TRILOBITA. 

 Family ILLiENIDiE. 



ILL^NUS DANIELSI, n. sp. 



Plate VII, Fig. S, dorsal view of a magnesian limestone cast ; 

 Fig. 4, anterior view oi same specimen; 

 Fig. 5, pygidium oi same, 



Species, judging from our specimen, below medium size. Head 

 short and much inrolled, length from the neck furrow to the 

 anterior part, between the eyes, less than one-third the width. 

 The head is abruptly bent inward from a line connecting the 

 anterior part of the eyes. Glabella depressed convex, between 

 the eyes, on top and re-curved in front. Dorsal furrows extend 

 in almost parallel lines from the posterior part of the shield, to 

 a shallow pit on the inner side of the anterior central part of 

 each eye. Eyes large, distant, prominent and situated close to 

 the posterior margin of the head. Palpebral lobe rounded. 

 Facial suture extends from a point in the occipital furrow, be- 

 hind the middle of the eye, inward to the posterior portion of 

 the palpebral lobe, where it makes a rather sharp angle and 

 then gently curves to the anterior part of the eye, then bends 

 almost at right angles and then curves to the anterior margin, 

 slightly within the line of the eye. Cheeks small, abruptly bent 

 down and backward so as to extend, laterally, only a little be- 

 yond the outer lines of the eyes. 



Thoracic segments ten, narrow; axis broad, depressed convex, 

 full half the width of the animal, and a little wider at the an- 

 terior than at the posterior segment. On each side of the axis 

 there is a flat space, about one-fourth the width of the lateral 

 lobes, and then the pleurae are bent gently backward. 



