CERATIOCARIS LUDENSIS. 33 



This fine specimen is from the laminated mudstone of the Lower-Ludlow 

 series, at Church Hill, Leintwardine, near Ludlow, associated with GraptoHtes. It 

 was obtained many years since by the late Mr. H. Pardee, and is preserved in the 

 Ludlow Museum. 



On careful examination of this large specimen of G. Ludensis, H. W., we 

 have reason to believe that the caudal appendage which appears longest in the 

 fossil was not really the longest, or the true telson, but was one of the " laterals " 

 or stylets. Hence the whole animal was probably much longer than our first 

 estimate made it. 



PI. I. Ceratiocaris Ludensis, H. W. (Ludlow Museum.) Two thirds of the 

 natural size. (See also a portion, in PL IX, of the natural size.) Leintwardine. 

 Greenish-grey, hard, micaceous, calcareous mudstone, with many small Grapto- 

 Htes (Monograptus priodon), nearly all lying in one direction. There are also other 

 little marks of organic origin, and a few obscure impressions of larger fossils. 



Seven abdominal segments (a and b) and three caudal appendages (c — g). 

 The former are laterally compressed ; the latter much damaged by breakage of the 

 stone. Six segments (a) have an ornament of raised wrinklets, longitudinal and 

 inosculating, but turning up and down on the anterior third. The seventh, or 

 ultimate segment (b), has only longitudinal wrinklets, interrupted and inosculating. 

 The opposite sides of five segments, a, are figured at aa, showing their epimera ; 

 and the opposite sides of the penultimate (part of a) and the ultimate (b) 

 segments, taken out from their embedment (being loose), are shown at bb. 



At c (in intaglio) and cc (in relief) is seen the distal end of what appears (at 

 first sight) to have been the longest of the caudal spines, smooth and depressed 

 for the distance of half an inch from the end ; then bearing three ridges, besides the 

 half-bm-ied thick edges ; and at first slightly, and then strongly marked by succes- 

 sive constrictions across the ridges, so as to present a series of several, nearly 

 equal, ridged tubercles, set more or less obliquely across the spine. These bear no 

 definite marks of pitting. See PL IX, fig. 1 h, for an enlarged view of this piece. 



In the next portion upward (d) of this caudal spine the outside has quite gone, 

 and the internal structure is obscure. A small piece of what appears to be a 

 smooth, ridged, caudal spine appears (not seen in PL I) in the stone near this 

 part, at a higher level, and almost in a fine with another caudal spine (p). What 

 remains of the upper or proximal end (e) of the caudal spine c, d, is partly 

 convex, and roundly truncate, ending apparently with such a joint as the stylets 

 or lateral caudal spines have at the top. Downwards it has been squeezed flat, 

 showing obscure lumpy ridges and confused internal structure. For about an inch 

 before it is concealed by the matrix (d) it is modified by another fossil (fragment 

 of Eurypterus ?) having lain across it. 



This caudal spine (o, D, e) seems, from the apposition of its rounded top to 



