PROCEEDINGS OF UKITED STATES NATIONAL MUSEUM. 313 



pleura appears to be of tlie regular type. Middendoi'fs figures of the 

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

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



In the sole si^ecies of this genus, the ovary is convoluted and suigle. 

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

 hranchiic and the side of the foot. They are placed in the vicinity of 

 the fifth hranchia from the i)osterior end of the row. There are no slime 

 glands. The organ of Uojanus appeared to he represented by a glandu- 

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

 l^lain, drawn down to corners behind on each side, but without fla]>s. 

 Veil narrow, thin, plain, x)roduced in a flai) on each side of the muzzle. 

 Mantle-edge narrow, plain. Branchiae about sixty on a side in a ro^^' as 

 long as the foot, xinus papillate, median, with a ridge extending eacli way 

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



Katherina tunicata. 



Chiton tunicatus\\(xoA, Gen. Conch, p. 11, fol. 2, f. 1, 1815; Ind. Test. Cliiton, 



pi. 1, f, 10, 1828 ; lb. ed. Haul. 1856.— Sowerby, Beecliey's Yoy. Zool. p. 



150, t. sU, f. 15, 1839.— Reeve, Conch. Icon. Mon, Chiton^ f. Gl (good), 1847. 

 Chiton {Phccnochiton, Hamachiton, riatysemus) tun ica ttis Midd. — Mai. Ross, i, p. 



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

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



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

 Katherina Dotif/lasiw Gray, P. Z. S. 1847, p. 69. 

 Katherina tunicata H. & A. Adams, Geu. Roc. Moll. :, p. 479, iii, pi. 54, f. 6, 



1854. 



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

 antice inter lam. sutur. projecta, tenuissime punctulata; area centr. 

 rotuudatis, quincuncialiter fortiore punctata; ar. lat. hand definitis, fere 

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

 ad caudam angiilatim sinuatis, prsecipue utr. lat. unifissatis, sed inter- 

 dum in lobas ii'regulares ^, -J, |, f, i fiss.; v. centr. 1-, ant. 7-fissatis; 

 laminis prcelougis, antice valde projectis, acutis, extus striatis, fissuris 

 parvis, suftultis, ad subgrundas solidas, curtissimas valde spongiosas, 

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

 tis, prffilongis; zona nigra, supva valvis tenui, omnino lievi. Lon. 50, 

 Lat. 20 mm. 



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

 side of the peninsula of Aliaska to Port Moller, 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 shell, characterized, when fresh, 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- 



