492 H. Woodward — On a New Long-eyed Trilobite. 



head- shield, not upon these horn-like prominences which have, 

 however, a strong resemblance to the eye-pedicels of Trilobites. 

 (Compare Figs. 1, 4, and 7, Plate XXI.) 



Turning once more to the Trilohiia, we have in our Plate, Figs. 3 

 and 5, illustrations of two species of Asaphi, A. expansus (Fig. 3), 

 and A. Koivaleioskii (Figs. 4 and 5), in which the specific difference 

 appears to consist in the development of the eye-stalks in the one 

 case and their suppression in the other.^ 



Mr. Hollier's specimen of Calymene (Fig. 1) and the old Calymene 

 Blumenhachii (Fig. 2) offer a perfectly parallel case to that of the two 

 Eussian forms of Asaphi (Fig. 3-5). I am, of course, assuming that 

 some out of the many specimens of Calymene Blumenhachii (perhaps 

 by far the larger proportion) had sessile eyes placed upon the cheeks 

 of the glabella ; but I feel equally certain that so soon as Mr. Hollier's 

 discovery is made known, many long-eyed Calymene will be discovered 

 at Wenlock ; perhaps they already exist in the cabinets of some of 

 our Dudley friends, quien sahe f 



It will be for Mr. Salter to reconsider this genus when, with a 

 fresh stock of health, which he has been accumulating at Malvern 

 and in Wales, he again vigorously takes up his pen and pencil and 

 completes his admirable Monograph on the British Trilobites. 



In order however to protect Mr. Hollier's discovery from being 

 overlooked for want of a distinctive appellation, I propose to christen 

 his specimen Calymene ceratophthalma,^ which (although a rather 

 long name) expresses well its specific peculiarity. 



In consequence of the terminations being somewhat cut away by 

 the man who developed the specimen, I am unable to define well the 

 extremities of the eye-pedicels, but I have used dotted lines in the 

 Plate to indicate what their perfect outline appears to have been. 

 With respect to the formation of the eye-stalk it will be observed, 

 by referring to Fig. 4, that it is partly composed of the glabella and 

 partly of the cheek, or "facial" portion of the head-shield, the suture, 

 which divides these regions, being clearly seen in the figure passing 

 up each eye-stalk ; the extension of the border of the glabella, form- 

 ing what may be aptly called the "superciliary border" above the 

 cornea of the eye, whilst the prolongation of the cheek or "facial" 

 border forms the lower and exterior portion of the pedicel. 



If we compare the two forms of eye-stalks we shall perceive that 

 in A. Koioalewskii (Figs. 4 and 5) the eyes are very erect, and diverge 

 but slightly from each other; in Calymene ceratophthalma (Fig. 1) the 

 eyes-pedicels are directed forwards, being little raised from the plane 

 of the body, and diverge widely from each other, curving outwards and 

 forwards. I am inclined to tlie opinion that the depressed plane of 

 the eye-stalks is partly due to compression, and that, normally, they 



^ In the 4tli edition of Murcliison's "Siluria" (p. 357), a figure is given of the 

 ordinary form of Asaphus expansus^ Wahl., in wliich the eyes are quite sessile, and 

 not at all elevated above the glabella, as represented at Fig. 3 in our Plate. Another 

 example there figured, called variety comutus^ has its eyes more elevated than in our 

 Fig. 3, but less so than in Figs. 4 and 5, PI. XXI, The eyes in this front vievir are 

 seen to diverge laterally, as in our Calymene ceratophthalma. 



' From K6pos, a horn: and, '0(t>du\/ihs, the eye = horn-eyed. 



