nORN EXPEDTTrnX — PALyF,0\TOr-nr)Y. Ill 



Ohs. — This spocips T had orit;iiially i-o^ai'dpfl as a SfropJioiiioia, alliod to 

 S. ftniiciilata, INIcCoy (T.), l)iit dpspit-p its StropJioinc)ia-\Wc ontliiio and tlif partial 

 closure of the foramen, yet by its internal characters it must be referred to Orfhis, 

 among species of whicli it presents certain analoijy to O. alata, S(^\v., and O. pliilipi, 

 Davidson, diflfering from both by its crowded radial ornamentation. Tlie conca\o- 

 convex valves separate it from tlie alate Strophomena' willi semicirrulai- outline, 

 e.g., fiinhiiJata, pecfen, and applaiiata. 



Class Cri'stacf-a. 



Order Trilobita. 



Asaphus thorntoni, Eth., fils. 

 Ref.—\\\., p. 8, pi. ii., 1892. 

 Loc. — Tn limestone and ((uartzite, Middle Valley, Tcmjic Downs. 



Asaphus illarensis, Eth., ills. (Plate III., Fi-s. -iXa, 21/'.) 



Re/.— v., p. n, pi. i., fi- 1. 



Perhaps the most important paheontolooic.al discovcT'y made by the Expedi- 

 tion is that of an entire trilobite, as hithci'to these fr>ssils h.i<l only been known 

 by pygidia, and a few fragments of the thorax. Tlie sjiccinicn hcrrin (igurcd 

 removes any doubt which may have been entertained as to the generic location of 

 tlie tail-piece on which Mr. Etlieridge established his AsapJiiis illaroisis. 



The facial suture is proper to /lsap/i//s, but in this S])ecies pi-occ(>ds .almost 

 direct from the eye to the fi'ont margin. There ai'e seven tluir.-icic segments, but 

 as the specimen is broken at the seventh segment and the t.ail forced back, it is 

 possible that the eighth segment had become detached. 



Head, thorax and tail of al)Out equal length. (Jlabella clawnte. Thorax of 

 seven (eight ?) segments; tlie axis as wide as the pleura^ very convex, slightly 

 tapering, nearly parallel-sided ; ])leura' nearly straight, ll.aftcnrd, slightly produced 

 and bent down at their ends, grooved throughout. 



Total length, G2 mm. ; greatest width, 40 mm. This species does not seem 

 to have attained so l.ii-ge a size as some of its congeners ; but a specimen con- 

 sisting of six thoracic and pygidium has .a length of 10 mm., coircsponding to ,a 

 total length of 80 mm. 



