BRITISH FOSSILS. 



Dec^ade XI. Plate VII. Figs. 1-5. 



ANGELINA SEDGWICK I. 



[Genus ANGELINA. Salter. (Sub-kingdom Articulata, Class Crustacea. Order 

 Trilobita. Family Conocephalidse.*) ])epress8d, head smooth, and with long posterior 

 spines ; eyes small, sub-median, without ocular ridge ; glabella lobeless. Body segments 

 14-15, with an angular fulcrum, facetted for rolling up. Tail of few (four or five) 

 segments. Labrum emarginate.] 



Diagnosis. A. ovata, segmentis frunci 15, axi quam pleuris paullo 

 angustiori. Cauda ulrinque bispinosa. 



Synonyms. A. Sedgwicki, Salter, Siliiria, 2nd ed., 1859, p. 53, foss. 

 9, fig. 2. A. suharmMa, ib., fig. 3 (specimens pressed laterally and 

 lengthened). A Sedgicichi, Memoirs Geol. Snrv., vol. iii. (ined.) pi. 7. 



The new forms illustrated on our phite were part of the results of a 

 survey by myself in 1853 of tlie " Liiigula Flags " and overlying beds 

 in the mountain region extending from Tremadoc to Ffestiniog, and 

 thence to Arenig-fawr, west of Bala. They have since been collected 

 by the hundred, and are really common fossils. 



The affinities of the genus are equally balanced between Olenus 

 and GonoGoryphe. Angelina differs from Olenus by having the 

 pleurae grooved and facetted for rolling up, instead of flat and pro- 

 duced into points ; nor do we know of any Olenus that is totally 

 without glabella furrows. It is this latter character, with the occa- 

 sionally spinose tail, which distinguishes it from Gonocoryphe ; but 

 this is combined with some characters of habit, such as the long 

 head spines, less marked cephalic furrows, both axal and marginal 

 (indicating probably a thinner crust), and much less deflexed pleurse, 

 with the fulcrum nearer the axis. Angelina, too, wants the ocular 

 ridges of Gonocoryphe. From A rionellus the less number of body 



* The Conocephalidce (Salter) differ essentially from the Calymenidce by the variable 

 but larger number of body rings, and the course (posteriorly) of the facial suture. They 

 seem to have had a thinner crust, and, as a character of habit, resemble the Oknidce in 

 the long head spines and often sub-spinous tail border. 



[XL vii.] 11 G 



