During last summer I visited the interesting and ancient town of Ludlow, where, under the guidance of Mr. Robert Lightbody, F.G.S., I had the opportunity of seeing the admirable Public Museum, belonging to the Ludlow Natural History Society, and also the rich private collection of Mr. Lightbody and that of Mr. Humphrey Salwey. In the Society's Museum, my attention was directed by Mr. Lightbody to a truly remarkable fossil from the collection of Mr. Henry Pardoe, and obtained by him from the Lower Ludlow, Church Hill, Leintwardine. It consists of seven body-segments and three caudal spines, of the largest example of Ceratiocaris I have ever seen; exceeding in size the C. Bohernicus of Barrande, or C. Murchisoni from the Upper Ludlow Rock, Ludlow and Wenlock Shale, Dudley, figured and described by me in the Geological Magazine, 1866, Vol. III., PI. X., Fig. 8, pp. 203–205. The figure (taken from a sketch made at the time) given on Plate III., Fig. 3, being only one-third the size of the fossil, conveys but a very inadequate idea of this interesting Crustacean remain. The seven body segments together measure eight and a half inches in length, and nearly two inches in breadth; they are nearly quadrangular, and are covered with fine and delicate parallel slightly waved striæ. The first segment is three-quarters of an inch long; the second, half an inch; the third, three-quarters of an inch; the fourth, fifth, and sixth, one inch each in length; and the seventh, two and three-quarter inches long.