PROCEEDINGS OF UNITED STATES NATIONAL MUSEUM. 327 



The gill-rows extend forward two-thirds the length of the foot. They 

 contain about twenty-seven branchiae on each side. The mantle-edge is 

 very narrow, hardly distinguishable around the head. There is no veil. 

 The edge of the muzzle is inarginated all around, and drawn into flaps 

 at the posterior corners. 



Tonicella submannorea. 



Chiton submarmoreus Midd. Bull. Acad. Sci. St. Petersburg, iv, No. 8, 1846; 

 Mai. Ross, i, p. 98, 1847; lb. Sib. Reise, p. 178, pL xiv, f. 7-10, xv, f. 7-8, 

 1851. 



Chiton insignis Reeve, Conch. Icon. Mou. Chiton, pi. xxii, No. 149, f. 148, 1>47. 



T. t. ut in forma precedent e, sed testa externa ex rosea flavoque alba, 

 maculis flammulisque sed runs, sed albis picta; tegmentum zonae laevius- 

 cnlum, nitidulum, flavuni ant fuscum pictum. 



Hab. — Japan and the Okhotsk Sea, Aleutian Islands to Sitka and 

 Puca Strait. It has not been found north of the Aleutians or south of 

 Washington Territory. 



In the description of this form, Middendorf, in distinguishing it from 

 T. marmorectj seemed to overlook its relations to T. Uneata, from which, 

 for some time, I was indisposed to specifically separate it. The peculiar 

 color of the valves is reproduced sporadically on some valves of T. line- 

 ata in occasional specimens; though these may be due to hybridization. 

 The dentition, elsewhere figured, indicates, however, that the two forms 

 are specifically distinct. The soft parts are very similar to those of T. 

 marmorea in every respect except that the openings near the anus were 

 absent. The specimen was a male, and the structure of the spermsac 

 recalled that of Acmcca. Some of these differences may be sexual; at 

 all events, the subject requires investigation from living specimens. 



Tonicella saccharina. 



Tonicella saccharina Dall, Proc. Nat. Mus. p. 2, Jan. 1878. 



T. t. parva, oblonga, tota superficie saccharina rufo et albescent e picta ; 

 mucrone submediano, inconspicuo; ar. lat. inconspicue elevatis, ar. dors, 

 sanguinosis, aeque quincuncialiter lente reticulata; v. ant. 10-11-, v. 

 post. 8-10-, v. centr. 1-fissata; dent. parVis, spongiosis; Binnp&rvo; sub- 

 grundis spongiosis, mediocris; zona coriacca ut in TonicdUv aliis. 

 Branchiis mediis. Lon. G.5, Lat. 4 mm. 



Hab. — Aleutian and Shumagin Islands; Kyska, Unalashka, and Koni- 

 ushi, 3 to 13 fathoms on stones! St. Paul. Pribiloff Ids., 15 fathoms. 

 Seven specimens examined. 



This interesting little species has the lustre of rock-candv, through 

 which the microscopic reticulation is barely perceptible. It is marked, 

 in all the specimens obtained, by the red wine colored dorsal areas con- 

 trasted with a waxy white color of the lateral areas, rendering its rec- 

 ognition easy. The girdle is dark, leathery, narrow, slightly pubescent, 



