870 E. ETHEE1DGE, JUN., ON THE OCCTXEEENCE OF A 



Under the Macrura the authors describe Anthrapalamon ? gracilis, 

 which differs from A. Grossarti, Salter, iu the absence of the 

 central spine and in the structure of the antennae, although it 

 possesses the serrated lateral border of the carapace. Prof. Dana, 

 Messrs. Meek and AVorthen tell us, considers Anthrapalcemon to be 

 more nearly allied to JSglea and Oalathea than to Palcemon. These 

 forms are all from the base of the Coal-measures of Grundy County, 

 Illinois. 



1866. Messrs. Meek and "Worthen again published descriptions 

 of the before-mentioned fossils, but now accompanied with good 

 figures and supplementary remarks bearing on them, in the second 

 volume (Palaeontology) of the Illinois Geological- Survey Peport, as 

 follows : — 



Acanthotelson Stimpsoni, M. 4' W. p. 401, t. 32. f. 6, a-f. 



„ maequalis „ p. 403, t. 33. f . 7. 



Palseocaris typus, M. $ W. p. 405, t. 32. f. 5, a-d. 

 Anthrapalaemon gracilis, M. <$* W. p. 407. t. 32. f. 4, a-c. 



1867. Mr. H. Woodward follows Prof. Huxley in placing Pygoce- 

 phalus near Mysis among the lower Decapoda, and does not consider it 

 to have any affinities with the Stomapoda*. The cephalothorax has 

 seven pairs of appendages, and two pairs of external mouth-organs. 

 Each appendix consists of two parts — the limb proper, or endopodite, 

 and a filamentous appendage, or exopodite. Poth the antennae and 

 antennules have two basal joints, with a broad oval scale externally. 

 The epimera of the abdominal somites are produced to a point. Mr. 

 "Woodward shows that there are no differences of generic value be- 

 tween Anthrapalcemon and Pcdceocarabus, as imagined by Salter, 

 and that the latter must be reduced to a synonym of the former. 



1868. In a " Supplementary jSTote on some of the Grundy-County 

 Crustacea, &c, formerly described " f, Messrs. Meek and Worthen 

 give some additional information on the genera Acanthotelson and 

 Palceocaris, and propose a new species of the former genus, A. Event. 



1868. The third volume of the Illinois Geological-Survey Report 

 contains further notes and figures of the curious Crustaceans of 

 Grundy County, Illinois J, including a figure of the new species 

 Acanthotelson Eveni. The sum of the evidence at the disposal of 

 Messrs. Meek and "Worthen appears to be that Acanthotelson "ap- 

 proaches some of the lower types of the macrural Decapoda ; " but 

 they leave it with doubt in the " Isopod group of the Tetradecapoda." 

 As to Pedeeocaris, there appears to be some diversity of opinion. 

 Prof. Dana and Dr. Stimpson believe " that it is a low embryonic 

 type of the Macrura, in which the carapace is not developed." The 

 authors themselves consider that it exhibits a combination of De- 

 capod (Macruran) and Tetradecapod characters, having " the caudal 

 appendages, anteriorly directed thoracic legs, the antennae and 

 general aspect o a Macruran, with the distinct head, divided thorax 



* " On the Crustacea from the Glasgow Coal-fields," Trans. Geol. Soc. Glas- 

 gow, vol. ii. p. 2-10, pi. ,S. 



t American Journ. Sc., 2nd series, vol. xlvi. p. 28. J Pp. 549-555. 



