256 DESCRIPTION OF THE SPECIES OF PTERYGOTUS 
conspicuous on the opposite surface, and which seem to divide the 
plate into laciniz, a. The plate is indented at its basal end, corre- 
sponding to the central depression (ridge in the cast) of the preceding 
joint. This joint is very irregular in shape, the lobes on one side, @, 
being single, on the opposed side ¢ double. Both are marked with 
minute plicee near the edges. 
Locality —The above-mentioned fragments have all successively 
come to light during the active researches of the Ludlow geologists 
in the quarries of LOWER LUDLOW Rock at Leintwardine, particu- 
larly in one at Church Hill. There are many new Crustacea to be 
described from the same quarry, of one of which the head portion 
has been accidentally introduced into this plate. Plate XIII. 
[Plate 24] fig. 17. See also p. 190, supra. 
PLaTes X. [PLATE 21], XI. [PLATE 22], AND PART OF NIII. [PLATE 24]. 
PTERYGOTUS PUNCTATUS. 
P. magnus, (5-6 pedalis ?) capite 
mots prominulis ornatis,—in articulis posticis per totum annulum sparsts , chelts 
antennarum elongatis, palpis longifimbriatis. Pedibus natatorits articulo 
terminal elongato, penultimo expanso. 
(2), segmentis omnibus squamulis re- 
Of this very large and distinct species various fragments have 
from time to time come to light, and have been communicated by our 
friends, Messrs. Lightbody, Cocking, and Marston, of Ludlow, and 
especially from the cabinet of H. Pardoe, Esq. 
They are from the quarry at Leintwardine, Shropshire, in the 
Lower Ludlow Rock, where many fine starfish and other rarities have 
been newly discovered. (Siluria, 2nd edition, p. 140.) 
There is evidence of at least three, if not more, of the thoracic 
rings. The hinder segments were decidedly longer in proportion to 
their width than in the P. anglicus or P. gigas. We have also the 
swimming paddles, which, without the great coxal joints, were seven 
inches long, expanded in the penultimate joint and attenuated at 
their tips; of the mandibles, the palpi of which are strongly fringed 
with long curved processes, and of antenna, with slender pincers at 
their terminations, and armed with numerous small conical teeth. «As 
all these parts present distinctive peculiarities from other species, and 
as the tuberculation on the various specimens found in this bed 
agrees in character, it is fair to combine them as a single species, and 
figure them all upon one plate. 
