PKOCEEDI.NGS OF UNITED STATES NATIONAL MUSEUM. 329 



lata; zona angusta, olivaceo-cinereo maculata, confertim spinulis minutis 

 ornata, oculo iiudo sublaevis ; submicroscopio epidermis dorsalis pube^- 

 ceiis, stroma spiuulis rarioribus latentibus erectis; mucro indistinctis 

 in STimuia tameu linea mediana val varum intermediarum superue sulcus 

 decurrit linearis, longitudinalis, argute incisus ; sinu jugali modico, alto, 

 baud laminato, conspicue spongiosa, subgrundis minimis, maxime spon- 

 giosis; V. ant. 11-, post. 11-, ceutr. l-flss-. Branchise cire. 22, snbambi- 

 entes. Lon. 16, Lat. 5 mm. Div. 140°. 



Hah. — Sbantar Bay, Okhotsk Sea, Midd. ; Aleutian Islands eastward 

 to Sitka Harbor, low water to 12 fathoms on stones and shells; Dall! 

 ]S^inety-three specimens examined. 



This very remarkable species is very prettily marbled with olive, 

 chestnut, and blue ; the girdle generally dark olive, dashed with ashy 

 spots and in hne specimens having a pubescent appearance. The slit 

 is occupied by a cartilaginous substance of a dark brown color, most 

 visible from within. The branchiae aj^pear to reach nearly to the head. 

 It is quite ijossible that it may reach as far >south as Puget Sound. 



The soft parts are yellowish white. The gill-rows extend three-foui^ths 

 of the length of the foot forward fiom theii' posterior termination, and 

 each contains about twenty-two branchiaB. Mantle-edge thick, plain; 

 veil small, plain. Muzzle small, plain, with two large squarish lappets 

 at the posterior corners. The supposed oviducts open on each side 

 tlu'ough a smaU rounded papdla in the vicinity of the third or fourth 

 branchia counting forward, and between the line of the gUl-row and 

 the side of the foot. 



Genus CH^TOPLEURA Shuttleworth. 



Chwloplenra Sliuttlow. Bern. Mitth. Juni 1853. Ty^je Chiton Penmanus Lam. 

 <^Chcetopleura H. & A. Adams, Geu. Kec. Moll, i, j). 475, 1854. 

 <^Acanthapleura Gray, P. Z. S. 1847, p. 67. 



Testa Ischnochitoni simiUs; zona plus minusve pilosa. BrancMse 

 ambientes. 



Chaetopleura Hartwegii. 



Chiton Hartwegii Carpenter, P, Z, S. 1855, p, 231. 



Trachydermon Hartwegii Cpr. Suppl. Eep. Br. Assoc. 1863, p. 649. 



C. t. colore olivaceo, ciaereo sen rufo-fusco seu cupreo-viridi, ssepe 

 elegauter maculoso; intus, intense caeruleo-vkidi; mucrone mediano 

 satis elevato; Aalvis singulis tumentibus, elegauter arcuatis, apicibus 

 conspicuis, suturis marg. distinctis; ar. diag. liaud nisi costis tumenti- 

 bus subobsoletis discernendis ; tota superficie super granulis minimis, 

 sub lente solum distinguendis, granis parvis ubique sparsis ; super ar. 

 diag. et v. term, granis majoribus irregulariter verrucosis ; intus v. post. 

 9-12-, ant. 10-11-, centr. 1-fissatis; dent, solidis, obtusis, interdum subru- 



