44 AMICULA. 



Girdle thin, smooth ; adults generally having more or less devel- 



lut always sparsely scattered, small hunches of hairs. 

 Length 50, breadth 3.1 mill. 



ng snnfhwtr'l in the Pacific region to Hay- 

 id St. Paul Islands, Bering Sea; in th* Atlantic to Cape 

 Cod, Massachusetts, in 5-30 fms., mud and stones. 



Chi- ''"jBROD. &Sowr,, /.)..!. Journ. iv, p. 368 (1829); 



Conch. Illustr., f. 128, 128a; Zool. Beechey's Voy., p. 150, t. 41, f. 

 14. A mi !,i rextita GRAY, P. Z. S. 1847, pp. 65, 69, 169. H. & 

 A. AD., Gen. Rec. Moll, i, p. 480 ; iii, t. 55, f. 2. STIMP., Sh. of N. 

 EngL p. 29. CPR., Bull. Essex Inst. 1873, p. 155. DALL, Proc. 

 U.S.Nat. Mus. 1878, p. 307; p. 299, f. 43 (dentition). Chiton 

 emersonii Connor v, Bost. Journ. Nat. Hist, ii, p. 83, t. 3, f. 10 

 (1838). Amicula emersonii GRAY, P. Z. S. 1847, p. 69. BINNEY'S 

 edit, of GOULD, Invertebrata of Mass., p. 264, f. 527. Chiton emer- 

 sonianus Gouu>. Inv. Ma-s., p. 151, f. 19. REEVE, Conch. Icon., 

 t. 11, f. 62. titi)n/i*iiiella emersonii CPR., Bull. Essex Inst. 1878, p. 

 165; Ann. Mar. X. II. (4), xiii, p. 122 (1874). Chiton amiculatits 

 REEVE, Conch. Icon., t. 11, f. 59, not C. amiculatus Pallas. 



The relations existing between vestitus, emersonii and pallasii have 

 been clearly stated by Dall, who writes as follows : *' Much has been 

 said about the presence or absence of pores and hair-tufts. I find 

 examination of a series that the young emersonii is usually 

 smooth, the large ones always setiferous. These seta? are, as 

 described by Dr. Gould, in two rows on each side, or rather six in 

 all if we count the pretty constant tufts behind the exposed apices of 

 th- shell. These rows are (1) two behind the shell points as above; 

 (2) two, one on each side at the posterior angle of the submerged 

 expansion of the valve; (3) a series, more or less irregular, along 

 the margin of the girdle. Beside this, in old ones, there are irre- 

 gular tufts all over the girdle, and some of the regular tufts may be 



" This species is very close to A. jill<in!i, but is distinguishable by 

 the larger and laterally much more expanded exposed portions of 

 the valves, by it- Hatter f.trm. ami proportionally spar.-eraiid longer 

 seta?. When dry. the whole form of the valves is visible in > 

 from above, like the bones of a Peruvian mummy: in ;/<////.//, how- 

 ever, the inieLMimeiit is so niueh more eoriaceous and thick, that in 

 :ien- hardly anything of these outline^ is visible." 



