230 abstracts: paleontology 



His first summary of i88i^ is reviewed and corrected, together with 

 later papers^ discussing his various discoveries in this subject. The 

 highly organized trilobite, Neolenus serratus (Rominger), from the 

 Burgess shale quarry opened by Dr. Walcott, near Field, British Colum- 

 bia, several years ago, shows most graphically in the ten plates devoted 

 to its illustration the highly specialized development of appendages, 

 which is also figured in plates of the Ordovician trilobites, Isotelus, 

 Triarthrus, Calymene, and Ceraurus. In the figure of Neolenus the 

 appendages include antennules, caudal rami, endopodites, epipodites, 

 exopodites, exites, and protopodites. The evidence of appendages 

 is supplemented by numerous figured sections of Ceraurus and Caly- 

 mene. 



After discussing the mode of occurrence, conditions of preservation, 

 manner of life including methods of progression, food, defense, and 

 ofifense, the author describes species with appendages, which include 

 besides the genera already mentioned, Kootenia dawsoni (Walcott), 

 two species of Ptychoparia including a new one, P. permulta, from the 

 Burgess shale quarry, Odontopleura trentonensis (Hall), Trinucleus 

 concentricus Eaton, and an unidentified Ordovician crustacean leg. 

 The work of C. E- Beecher with Triarthrus is reviewed in some detail, 

 and a different conclusion arrived at in certain features. 



In section 2 of the paper the Structure of the Trilobite receives at- 

 tention, the author again referring to Beecher and other writers in- 

 cluding Jaekel, Beyrich, Barrande, and de Volborth. He then dis- 

 cusses in detail the appendages, summarizing them as follows: 



Cephalic: (i) Antennules, (2) Antennae, (3) Mandibles, (4) Max- 

 illula, (5) Maxilla; Thoracic; Abdominal; Caudal rami. 



Further comparisons are with the recent Anaspides tasmaniae G. 

 M. Thomson, a Malacostracan from Tasmania, Koonunga cursor 

 Sayce, and Paranaspides lacustris Smith, also the parasitic crustacean 

 Cyamus scammoni Dall, illustrations of all of which are given. After 

 the extraordinary interest of the finely developed specimens in the plates 

 representing Neolenus, attention will be drawn by those of Isotelus, 

 Triarthrus becki Green, and other Ordovician trilobites, together with 



^ The trilobite: New and old evidence relating to its organization. Bull. Mus. 

 Comp. Zool. 8: 191-224, pis. I-VI. 1881. 



* Proc. Biol. Soc. Washington 20: 94. 1894; Smiths. Misc. CoU. 57: 164-208, 

 pi. 24, figs. I, ic. 1912; op. cit. pi. 6, figs. I, 2. 191 1 ; op. cit. pi. 24, figs, i, 10; 

 pi. 45, figs. I, 2, 3, 4. 1912; Text-book Pal. (Zittel), Eastman 2d ed. i: 701, fig. 

 1343. P- 716, figs. 1376, 1377. 1913; Smiths. Misc. Coll. 57: 149-153. 1912. 



