44 SAN niECJO SOCIETY OF NATURAE IIISTOUV 



Illing (V. (\) Notes on certain Trilol)ites found in tlu^ Stockingford 

 Shales. 



Brit. Assoc. Adv. Science, 83 Ann. Meeting, Sec. C, 1913. 



Abstract in Geo). Mag., Dec. V, vol. 10, p. 452, 1913. 



The author remarks that among tlie fossils found at Hartshill Hayes, numerous 

 forms occur, representing young stages in the development of certain Trilobites. Among 

 these are the following: 



1. Liostracus sp., similar to one described by G. F. Matthew. 



2. Holocephalina sp. The early stages of this genus possess a well-marked glabella, 

 widening anteriorly. 



3. ParaJoxiJis Ilicksii. 



4. Certain new forms of Agnostus. 



Jackel (0.) Ueber die Organisation der Trilobiten. 

 Zeitschr. Deutsch Geol., Ces. 53, 1901, pp. 133-171, plates 4-6. 



T^elier verselihiedene Wec'o Phvlogonetiseher Entwiekelung. 



Verhandl. des V. Internationalen Zoologen Congresses zu Berlin, 1901, pp. 1058- 

 1117, 28 figures in text. 

 Evolution of Trilobites, pp. 1086. 



The author illustrates Phacops, Agnostus and Olenus, fig. \os. 20-24. 

 On the evolution of Gigantostraca, p. 1105. 



liber die Agnostiden. 



Zeit. d. Deutsch Geol. Ges., vol. 61, 1909, pp. 380-401, figures 1-23. 



The author proposed Paragnostus with Agnosliis rex as its type. This was the type 

 of Corda's Condylopyge. He further proposed Dichagnostus with Agnostus granulatus 

 as the type duplicating Corda's Pleuroctenium. Tlie author gives the name of Mesag- 

 nostus for A. integer Beyr., which was used for Corda's genus Peronopsis. 



Miagnostus Jackel has the same type species, A. hie-vigatus Dalm., as Lejopyge Corda. 

 The new genus Leiagnostus, which has the same generic characters as Phalocroma 

 Corda. 



Metagnosttis erraticus and A. glahratus have the same short glabella with faint 

 basal lobes as Agnostus tardus Barr., which was the type of Corda's Arthrorhachis. 



Vogdes, in Am. Geol., vol. 9, 1892, p. 395, in his paper on North American species 

 of the genus Agnostus, uses this term for section IV. 



The author arranges the families as follows: 



1. Fam. Paragnostidae. Paragnostus n. gen., type A. rex Barr. 

 Dichagnostus n. gen., type A. granulatus Barr. 

 Diplagnostus, type A. plan'icauda Ang. 



Mesagnostus n. gen., type A. integer Barr. 



2. Fam. Metagnostidae. 



Metagnostus n. gen., type M . erraticus n. sp. 

 Hypagnotus n. gen., type A. luir-vifrous Linnrs. 



3. Fam. Agnostidae sensu stricto. 



Agnostus sensu stricto, type A. pisiformis I.inne. 

 Pseudagnotus n. gen., type A. cyrlnpyge Tullberg. 



4. Fam. Leiagnostidae. 



Ptychagnostus n. gen., type A. reticulatus Ang. 

 Miagnostus n. gen., type A. laevigatus Dalman. 

 Leiagnostus n. gen., type I., erraticus n. sp. 



