1870.] GEOLOGICAL SOCIETY. 91 



Mr. Billings next described the doublure or pleura in the Tri- 

 lobites, comparing it to that of Lwiulvs. He then proceeded 

 to describe a row of small scars and tubercles on the underside 

 of the pleurae, to which both Dr. Volborth and Dr. Eichwald 

 believed soft swimming feet or hard horny legs had been attached. 

 As these were first seen by Dr. Pander in a Russian Trilobite, 

 Mr. Billings has called them " Panderian organs." He thinks 

 soft natatory appendages may have been attached to these scars. 



Mr. Billings directed attention to the Frotichnites and CH- 

 mactichnites, which he thinks may now be referred to Crustacea 

 belonging to the division Trilohita. 



Finally, Mr. Billings described a section of a rolled-up Oi/mene 

 senaria, the interior cavity of which appears to be full of minute 

 ovate bodies, from l-80th to 1-lOOth of an inch in diameter. — 

 These small ovate bodies the author believes to be eggs. 



" Note on the palpus and other appendages of Aaajphus, from the 

 Trenton Limestone, in the British Museum." By Henry Wood- 

 ward, Esq., F.G.S., F.Z.S. 



Mr. Woodward, when comparing the Trilobite sent over by Mr. 

 Billings with specimens in the British Museum, presented by Dr. 

 J. J. Bigsby, F.R.S., discovered upon the eroded upper surface 

 of one of these, not only the hypostome exposed to view, but also 

 three pairs of appendages, and what he believes to be the palpus 

 of one of the maxillae. This furnishes an additional fact to Mr. 

 Billings's most interesting discovery, besides confirming its 

 con-ectness. 



Mr. Woodward considers the so-called " Panderian organs" to 

 be only the fulcral points upon which the pleurae move, and 

 showed that such structures exist in most recent Crustacea. 



He considered that the evidence tended to place the Trilobita 

 near to, if not in, the Isopoda Normalia. 



He remarked that the prominence of the hypostome reminded 

 one strongly of that organ in Apus, and suggested that we might 

 fairly expect to find that the Trilobita represented a more gene, 

 ralized type of structure than their representatives at the present 

 day, the modern Isopoda. 



Discussion. 



Mr. Woodward had carefully examined Mr. Billings's specimen 

 and agreed with him in considering that there was undoubted 

 evidence of the presence of walking-appendages under the thorax. 



