EEPOET ON THE POLYPLACOPHOEA. 33 



Plaxiphora carmichaelis, Gray, Proc. Zool. Soc. Lcmd., 1S47, p. 68, and Guide Moll. Brit. Mus., 1857, 



p. 186. 

 Chiton setiger, Gould, Wilkes' U.S. Explor. Exped., 1852, voL xii. p. 330, fig. 425 a, b. 

 Placiphora carmichaelis, Dall, Proc. U.S. Nat. Mus., 1878, p. 80. 



Habitat.— Station 306a. January 2, 1876. Lat. 48° 27' S., long. 74° 30' W. South 

 Chili. 345 fathoms. Blue mud. Bottom temperature 46°. 



The following three species of Blainville's, Cliiton albidus, Cliiton raripilosus, and 

 Chiton costatus, 1 are regarded by Sowerby and Gray as synonyms of this species, but 

 neither propose to adopt one of Blainville's names. The second species is from an 

 unknown locality, the other two apparently from South Australia. One or more of these 

 may perhaps be more nearly allied to Plaxiphora petholata, Sow. 



The Chiton biramosus of Quoy and Gaimard is certainly closely allied to this species, 

 if, indeed, it be distinct. They obtained it from Tasman Bay, New Zealand. 



All the other specimens are from the south-west of South America, Tierra del Fuego, 

 and Strait of Magellan ; var. fremblii is from Valparaiso, Chili, except Gould's, which 

 came from " Orange Harbour," and Gray's, which is stated to come from the Cape of Good 

 Hope. This is probably an error. 



Plaxiphora simplex (Carpenter) (PI. III. figs. 13, 13a-13e). 



Euplaciphora simplex, Carpenter MS. 



" Testa Euplaciphora modestce simili ; sed magis elevata, longiore ; lorica rudi, fusco- 

 purpureo varie maculata, ; jugo rotundato ; mucrone postico, planato ; ar. lat. vix definitis ; 

 valvis rotundatis, suturis magnis ; tota, superficie lasviore, sgepius detrita, subspongiosa ; 

 intus, valvis post, laminis satis elevatis, satis sinuatis ; valvis ant. 8— valvis cent. 1— fiss. ; 

 dent, acutis, vix suffultis ; subgrundaa curtis, spongiosis ; sinu valde angusto, laavi, planato. 

 Zona, pilulis minimis confertissimis quasi spongiosa, pilis corneis longioribus ad suturas et 

 sparsim instrueta. 



"Long. 1-35, lat. '7, div. 120°. Variat., long. 11, lat. "65, div. 100. 



" Habitat.— Tristan da Cunha (Mus. Cum., No. 2691)." 



Habitat. — Tristan Island, Tristan da Cunha. Shore. 



Station 135c. Off Nightingale Island, Tristan da Cunha. 100-150 fathoms. 



Dr P. P. Carpenter unfortunately died without publishing this definition of his species, 

 and having, through the courtesy of Dr Dall, had access to his manuscript, I have not 

 hesitated to transcribe his account, as it is only right that he should have all the credit of 

 his research. The specimens in the British Museum, to which he alludes, bear his manu- 

 script name. The Euplaciphora modesta, to which Carpenter alludes, is a new species. 



1 Diet, des Sci. Nat., 1825, vol. xxxvi. pp. 547, 548. 



(zool. chall. exp. — part xliii. — 1886.) Uu 5 



