184 Proceedings of the Biological Society of Washington. 



The present species seems to be abundantly represented in the Philip- 

 pines, and it seems strange that it has been overlooked in the past. It 

 is quite possible that it has been confused with Mitra paupercula Linnaeus, 

 from which it is at once distinguished by its less elongate outline and by 

 the presence of the spiral cords which are absent in paupercula. It is quite 

 distinct from M . tigrina Sowerby, M. litterata Lamarck, M. tornatelloides 

 Reeve, and M. virgata Reeve, which belong to the same group. 



We have seen the following additional specimens: Cat. No. 231,815, 

 U. S. N. M., 6 specimens, Cat. No. 231,814, U. S. N. M.,2 specimens, 

 all from Cataingan Bay, Dumurug Pt., Masbate; Cat. No. 231,851, U.S. 

 N. M., 1 specimen from China Sea, Now Wow, Formosa; Cat. No. 231,867, 

 U. S. N. M., 10 specimens from Sabtan Island, Batanes Group; Cat. No. 

 232,026, U. S. N. M., 1 specimen from Capunuypugan Pt., Mindanao; 

 Cat. No. 231,818, U. S. N.M., 1 specimen from Panabutan Bay, Mindan- 

 ao; Cat. No. 231,871, U. S. N. M.,2 specimens from Silino Island, Min- 

 danao; Cat. No. 232,034, U. S. N. M., 2 specimens from Little Santa 

 Cruz Island, Mindanao; Cat. No. 231,860, U. S. N. M., 1 specimen from 

 Port Ciego, Balabac; Cat. No. 253,699a, U. S. N. M., 1 specimen from 

 the Philippine Islands. 



Mitra arnaloti, new species. 



Shell very elongate ovate, white, with numerous axial bands and blotches 

 of rust brown, which increase in width and almost completely cover the 

 last whorl, excepting the periphery, which is encircled by an almost con- 

 tinuous broad white zone, the tip of the base also being white. Nuclear 

 whorls decollated, those succeeding increasing at first gently, then a little 

 more abruptly in size, which lends the extreme apex a slight mucronate 

 aspect. The whorls are marked by five moderately broad low, well round- 

 ed cords, which are separated by spaces a little wider than the cords. 

 The first of these is at the summit and the last immediately above the 

 suture. These cords become decidedly enfeebled on the last half of the 

 last turn. In addition to these cords, the whorls are marked by numerous 

 small vertical axial riblets, which differ markedly in strength and spacing. 

 At times they appear almost as varices. On the first four whorls the 

 riblets are reduced to almost incremental lines, but they increase steadily 

 in size beyond this to the last half of the last turn, on which they again 

 become enfeebled. Of these riblets, 56 occur upon the antipenultimate 

 turn. In addition to the above sculpture, the entire surface is marked 

 by exceedingly fine incremental lines and equally fine spiral striations, 

 the combination of the two lending the surface a finely reticulated cloth- 

 like texture. The narrow shouldered summit of the whorls renders the 

 suture well marked. Periphery inflated, well rounded. Base decidedly 

 concave in the middle, marked by the continuations of the axial riblets, 

 which become reduced to mere lines of growth at the anterior portion 

 of the spiral cords; the latter become successively stronger from the per- 

 iphery to the anterior portion of the base. There are about 22 of these on 



