I'RjCE: DINGS OF UNITED STATES NATIONAL MUSEUM. 313 



plcnyci appears to be of the regular tyi)e. Middendorf s figures of the 

 plates are inaccurate, and Gray's description in the Guide differs from 

 his more correct account in the Proc. Zool. Soc. (Cpr. MS.). 



In the sole species of this genus, the ovary is convoluted and single. 

 The ovarian openings are found on each side between the line of the 

 brauchi.ie and the side of the foot. They are placed in the vicinity of 

 the fifth branch ia from the posterior end of the row. There are no slime 

 glands. The organ of Bojanus appeared to be represented by a glandu- 

 lar deposit on the floor of the visceral cavity behind. The muzzle is 

 plain, drawn down to corners behind on each side, but without flaps. 

 Veil narrow, thin, plain, jiroduced in a flap on each side of the muzzle. 

 Mantle-edge narrow, plain. Branchiae about sixty on a side in a row as 

 long as the foot. Anus j)apillate, median, with a ridge extending each way 

 from it. Soft parts yellowish to deep orange, girdle shining blue black. 



Katheriua tunicata. 



Chiton tiDiicatus Wood, Gen. Conch, p. 11, foL 2, f. 1, 1815; lud. Test. Chiton, 



pi. 1, f. 10, 1828; lb. ed. Hani. 1856.— Sowerby, Beechey's Voy. Zool, p. 



150, t. xU, f. 15, 1839.— Reeve, Couch. Icon. Mon. Chiton, f. 61 (good), 1847. 

 Chiton {Phwnochiton, Hamachiton, Flat)/8cmus) t uvicatus Midd. — Mai. Eoss. i, p. 



98, t. X, f. 1-2, 1847. 

 Katheriua tunicata Gray, P. Z. S. 1847, p. 69; lb. Guide, p. 185, 1857. — Cpr. 



Suppl. Kep. Br. As. 1863, p. 648. 

 Eatherina Douglitaia; Gray, P. Z. S. 1847, p. 69. 

 Katlicrina tunicata II. & A. Adams, Gen. Rec. Moll, i, p. 479, iii, j)l. 54, f. 8, 



1854. 



K. t. extus, valvis postice fere rectangulatis ; area jugali longissima, 

 antice inter lam. sutur. projecta, tenuissime x)unctulata; area centr. 

 rotundatis, cxuincuncialiter fortiore punctata j ar. lat. hand definitis, fere 

 obsoletis; mucrone subpostice mediano, elevatoj intus, v. post, laminis 

 ad caudam angulatim sinuatis, praecipue utr. lat. unifissatis, sed inter- 

 dum in lobas irregulares J, -^, |, f, f fiss.; v. centr. 1-, ant. 7-fissatis; 

 laminis i^rjielongis, antice valde projectis, acutis, extus striatis, fissuris 

 parvis, suflultis, ad subgiamdas solidas, curtissimas valde spongiosas, 

 sulcis continuis; sinu altissimo, angusto, spongioso; lam. sutur. separa- 

 tis, i)r{elongis; zona nigra, supra valvis tenui, omnino lievi. Lon. 50, 

 Lat. 20 mm. 



Hah. — Kamchatka (Cpr.); the entire Aleutian group 5 on the north 

 side of the peninsula of Aliaska to Port MoUer, and on the south side 

 east to Cook's Inlet, and south to Catalina Island, California; low water 

 (chiefly), to 20 fathoms. Several hundred specimens examined. 



This unmistakable sheU, characterized, when fi-esh, by its broad shin- 

 ing black girdle and almost covered valves, is eaten raw by the natives 

 of the northwest coast, and is said to act as an aphrodisiac. The sup- 

 posed second species of Gray is merely a result of an irregular drying 

 of the girdle. The soft parts are of a salmon color in northern speci- 



