358 Annals of thk Caknkcie Museum. 



Sao (?) Lainottciisis Whitfield, l88i, liulletin American Museum Natural History, 



volume I, page 334, plate t,^, figures 9-I I. 

 Ai:;raulos [Arioite/lus) pustulatus Vodges, 1890, Bibliography of Paleozoic Crustacea 



from 1698 to 1889. Bulletin United States (Geological Survey, number 63. 



Although this is a very common species in the buff-colored dolo- 

 mite of the reefs, it occurs only rarely elsewhere, and seems to have a 

 restricted vertical range. Whole specimens, while not entirely lack- 

 ing, are rare, and the part usually found is that which Mr. Walcott 

 described in his original description oi Arionellus pustulatus, namely, 

 the cranidium. 'I'hese detached cranidia are wonderfully abundant in 

 the reef material on Isle La Motte, at King's Bay, Cooperville, at 

 Chazy and on Valcour Island. All of the whole specimens in this col- 

 lection are from a small ])ocket of rather crystalline limestone in a reef 

 about three miles south of Chazy village, New York. The following 

 is Walcott's original description taken from the second paper cited 

 above : 



" Arionellus pustulatus n. sp. 



" Glabella very convex, separated from the fixed cheeks by a strong 

 dorsal furrow : short glabellar furrows outline a frontal lobe on the an- 

 terior third ; a lateral lobe is indicated, on each side, by a short de- 

 pression or furrow parallel to the longitudinal axis of the glabella. 

 Fixed cheeks depressed beneath the level of the glabella. The strong 

 dorsal furrow, extending all around in front of the glabella, and the 

 rapidly sloping outer margin gives them a prominent, rounded, 

 almost tumid appearance. Occipital segment broad, depressed, sepa- 

 rated from the glabella by a narrow furrow. One segment of the 

 thorax is ])reserved in one specimen. It is strongly arched on the 

 axial lobe, ])leurye with an elevated posterior ridge, and depressed 

 anterior margin. Surface pustulose or finely tuberculated. Eyes, 

 movable cheeks, and pygidium unknown. 



" Formation and locality; Chazy Limestone, Chazy, New York." 



Although no figure accompanies this description, it is evident that 

 the author had in hand a cranidium of the species Whitfield de- 

 scribed in 1881 as Sao ? Lamottoisis. Whitfield's description was 

 accompanied by a dorsal and side view of the cranidium and a figure 

 of a thorax showing eleven segments, attached to which is a small 

 pygidium w hose details are left rather indefinite. 



In the description it is stated that there are twelve segments in the 

 thorax, but the ends of the segments on the pleura are not represented 



