THE NAUTILUS. 55 



angular periphery and convex base; thin, fragile, and of a pale, 

 somewhat transparent horn-color. Surface faintly marked with 

 growth-wrinkles, and under very strong magnification, showing an 

 excessively minute, close decussation of radial and spiral lines. 

 General outlines of the spire straight. Whorls 3^, convex. Colu- 

 mella reflexed above. Alt. 2, diam. 2.3 mm. 



Niijima, Izu. Types no. 849G3, A. N. S. P., from no. 1057 of 

 Mr. Hirase's collection. 



The rather acutely angular periphery is nearly in the middle of 

 the height of the shell. It is referred to the genus Sitala on account 

 of its spiral sculpture, which is, however, excessively minute. 



NOTE ON THE FAMILY SEPTIDJE. 



BY W. H. BALL. 



In the Report on the Mollusks of Porto Rico, I adopted for the 

 family Tritonidce of authors, the name Septidce, and for the typical 

 genus the name Septa, proposed by Perry in 1811. Perry's list of 

 species comprised six, beside which he mentions the Murex tritonis 

 of Linne (spelling the specific name tritonia, but his meaning is ob- 

 vious). His genus was equivalent to the genus Triton, as ,used by 

 authors of the first half of the 19th century. His largest and most 

 conspicuous species, which he compares with Murex tritonis, belongs 

 to the same group as the latter, which was generally accepted as the 

 type of the old genus Triton and reserved for it by Montfort when he 

 divided the genus, a year earlier than Perry. Therefore I accepted 

 Septa rubicunda Perry (= Triton nodiferus Lam.) as the type of 

 Perry's genus and applied the name to the congeneric species of 

 Porto Rico, since Triton is preoccupied. 



In an interesting and useful paper by H. Leighton Kesteven, re- 

 ferred to in the June number of the NAUTILUS, the author does not 

 accept the name Septa because Perry's first species is a Lotorium and 

 without argument is taken by Mr. Kesteven as type. He shows very 

 clearly that the name cannot be used for Lotorium, but does not 

 observe that I never proposed to so use it. I used it for the group 

 of Murex tritonis L., which is generically distinct from the group of 

 which Lotorium is a member, and which, as Mr. Kesteven shows, 



