228 RESEARCH IN CHINA. 



and forward to a little below the center and arches around a rather large, depressed 

 central space, terminating a short distance before completing a circuit of the space; 

 between the ridge described and the hinge-line are two spaces outlined by the main 

 ridge; of these the one nearest the anterior cardinal angle is somewhat depressed 

 and outlined by a shallow furrow extending at right angles to the hinge-line from 

 the ridge to the hinge-line. At a point about two-thirds the distance of the length 

 of the hinge-line a short and very slight ridge extends toward the hinge-line from 

 the main ridge ; between this and the slight furrow there is a slightly convex area. 

 Two minute tubercles occur on the long central ridge, one at the point where it 

 begins the loop to inclose the depressed central space and the other on the opposite 

 side of the depressed space. 



Surface minutely punctate under a strong lens. 



Entire width of valve, 2 mm.; length, 1.25 mm.; depth, about 0.5 mm. 



This species is distinguished from Aluta steropc [p. 227] by its wider valve and 

 the presence of the central ridge and depressed space. 



The specific name is given in recognition of the excellent and thorough pre- 

 paratory work that was done by Miss Elvira Wood in the preliminary study of the 

 Cambrian fossils from China and her work upon the Devonian crinoids. 



Formation and Locality. Middle Cambrian: (C82) A fine-grained bluish-black 

 limestone bowlder believed to have come from the lower part of the Ki-sin-ling 

 limestone [Blackwelder, igojc, p. 272] ; collected in river drift i mile (1.6 km.) south 

 of Chon-p'ing-hien, on the Nan-kiang River, southern Shen-si, China. 



Collected by Bailey Willis and Eliot Blackwelder. 



MEROSTOMATA. 



Genus AMIELLA Walcott. 



Amiella WAI.COTT, 1911, Smithsonian Misc. Coll., vol. 57, No. 2, p. 27. (Described and discussed 

 as a new genus.) 



Amiella yunnanensis Mansuy (MSS). 



After the printing of the paper on Middle Cambrian Merostomata, 1 I received 

 under date of March 22, 191 1, 2 a letter from Dr. H. Mansuy, geologist of Indo- 

 China, in which he stated that he had proposed the specific name yunnanensis for 

 the merostome associated with Redlichia chinensis. Doctor Mansuy also sent a 

 photograph of the illustration which will appear in his forthcoming report. 



'Smithsonian Misc. Coll., vol. 57, No. 2, 1911. 

 2 Received at Washington in 



