PKOCEEDINGS OF UNITED STATES NATIONAL MUSEUM. 297 



Ischuoradsia Cpr. uou Sliuttlovrorth. 



/. trifida Cpr. IMiuor lateral with uo outer whig, but a small process near the 

 ajicx of the shaft, which may represent it; inner wing normal; major lateral shaft 

 normal, cusp bidcntatc, with a spot behind the notch (Fig. 17 a); uncini rugose, 

 normal. Fig. 17. 



Lepidopleurus Cpr. iiou Eisso. 



L. Mevtensii Midd. Minor lateral with uo outer wing ; shaft cusped at ai)ex, inner 

 wing normal; major lateral with a simple cusp, shaft normal, deeply channelled 

 behind. Fig. 18. Fig. 13 a shows the appearance of the minor laterals and their 

 wings extending behind the rhachidian tooth as they do when in their natural posi- 

 tion. 



Iiepidoradsia Ci)r. {Lophyrus pars Adams.) 



L. aunlraVw Sby. Minor lateral with a singular mushroom-like cusp with rudi- 

 ment of inner and no outer wing; major lateral bidentate, shaft keeled with spatu- 

 late process; major uucinus short, broad, other Tincini rather small. Fig. 19. 



Callistochitou Cpr. 



C. paJmulatus Cpr. Minor lateral with a narrow inner wing parallel with and uo 

 wider than the shaft, cusped at the top, outer wing absent or represented by a 

 minute cuspidate process; major lateral with a simple cusp, shaft with an anterior 

 keel bearing a sublauceolate process. Fig. 20. 



CaUisioijlax, Ccrafophnnih:, and Xeircomhia not examined. 



Pallochiton Dall (= IlemphilUu Cpr. M.SS. nom. pneoc.). 



/'. Iiiiiiifi'uio.'iKS Cpr. Elinor lateral normal, bi-alate; major hitcral trideutate, shaft 

 normal. Fig. '^1. 



LoriTYKOiDr.v. 



Chiton Cpr. Lin. not Adams. Type C. fiihcrciilafu-s lAn. {LopltijruN H. & A. Ad. not Poll). 



C. artlcidatas Sliy. Minor lateral with no outer wing, shaft small, narrow, prone, 

 from which extends the greatly elongated cusped inner wing external to the rha- 

 chidian tooth; major lateral with a simple rounded yellowish cusp with a black 

 ujargin marked ]>y a peculiar spot; shaft normal, with an inner lateral expansion pro- 

 duced into a linguiform process; major uncinus broad, long, spatulate; outer unci- 

 ims traus%'ersely elongated. Fig. 22. Fig. 22 «, side view of rhachidian tooth. 



C. Sfolesii Brod. Minor lateral with expanded inner wing, shaft cuspidate, cusp 

 twisted and outer wing reduced to a portion of this cusj) or absent; major lateral 

 with an elongated simple cifsp, shaft thick, strong, keeled in front, keel bearing a 

 blado-sliaped process attached to the keel at two points, with a small foramen between 

 them: major uucinus .short, broad, somewhat plume-shaped. Fig. 24. Fig. 24a, 

 major uucinus, from below. 



C. Cinnivgii Frcmbly. Minor lateral norinal. with wings recurved above and on 

 each side; major lateral witli siniplo elongate cusp, shaft with a strong keel bent 

 outward l»elow and pvo(hiced above into a strong spoon-shai>ed process; two inner 

 uncini iiod>dos<' ; major uncinus with a slender and rather straight shaft. Fig. 25. 



C. ommUi-< live. Minor lateral; shaft with .small or nearly abortive wings, base 

 long and rccuiwed; major lateral with a simple rounded cusp, a keel on the shaft 

 bearing a spatnlat(> process; major uncinus featlier-sbaped, the vane on the inner 

 side. Fig. 2/1. 



Tonicia (Jray. 



T. deijann I'r(nil)ly. (lypc) Minor laurai Ical-.sliapcd, normal, ai^ex curved for- 

 ward; major latei'al with an orange, black-edged, rouiided, simple cusp with a spot 

 on the margin, f-haf? normal; major uncimis very much twisted and decurved, 

 spatulate. Fig. 'i7. 



Ea<hia, Fannyiri, Eudoxodiiton, ami ('r<isptdo<hit<iu imi cNaniiiicd. 



