ri. \\irn 



margins >lopinr harkwanU into a point, rrennlated on !. 

 anterior valve with !' radiatim: rid -.:- >iie concc-i. 



zig-zag stria*; lateral areas with two, on <-:i< I ulges 



crossed by line zig-zag stria- ; pOtterioi and median ar-;is with 

 fine oblique stria- divrr-m'j- t'n.ni the dorsal line out ward ami tor 



Md by others divrririni: outward and buekward forniing an 

 en-ine turned pattern. Length 88 inch. ; breadth .'51 inch. 



Color, mantle white; vakvs .irivyisli-blark with a white -tripe on 

 each side of the dorsal line ; interior Lrreenish-Une. 



A single specimen is in the ( 'olonial Museum, locality Dot st:r 

 (Button.) 



The following species probably belongs here, but I have seen no 

 specimen, and it has not been figured. 



CHITON (CH.ETOPLEURA) PLUMOSUS Gould. 



Shell brown-ashy, valves concave scarcely beaked ; anterior valve 

 ornamented with plumose radiating line; posterior valve small, the 

 apex marginal and having a submarginal rib on each side. Central 

 area large, ornamented with divaricating stria?, and lateral plumosely 

 co-united striae. Lateral areas small, bounded by asutural rib, striae 

 denticulated, interspaces clathrate. Girdle broad, leathery, furnished 

 with (bristly?) tubules. 



Length I'D, breadth '75 inch. (Old.) 



Habit'tt tnil-n 



Allied to C. ccelatu* Kv., which is said to be highly ornamented 

 with green and pink. (7. collei and C. mmcosus G. belong to the 

 same group. (Old., in Proc. Bost. Soc. Nat. Hist, vii, p. 165.) 



Section Guildingia Cpr., 1893, n. sect. . 



Guildwyia CPR., MS., and in Dall, Proc. U. S. Nat. Mus. 1881, 

 pp. 284, 288 (type G. obtecta Cpr. MS.) 



Shell and girdle like Plaxiphora, except that the valves are partly 

 immersed by the encroachment of the girdle. 



This section, like Fannettia in the genus Toniria, rests upon a 

 character of very little taxonomic value ; but as it is useful in break- 

 ing up a large genus for convenience in identifying, it has been 

 retained. 



