ball: mollusca and brachiopoda. 239 



follow the extremists and reject sucli a name as Cylichna Loven, on account of 

 the prior existence of Cylichnus Burmeister, as has been pointed out by Pilsbry 

 we must take the next valid group-naiue given to any part of the genus for the 

 generic name and let subsequent appellations take precedence only in conformity 

 with the order of their dates. 



Scaphander cylindrellus Dall, n. sp. 



Plate 8, figure 1. 



Shell subcylindric, thin, white, covered with a pale straw-colored periostracum, 

 the aperture as long as the shell, with one and a half visible whorls ; apex oc- 

 cluded except the last whorl and a half, which rise above and conspicuously over- 

 hang the spiral excavated callous deposit, which is also deeply concave at its distal 

 edge where it meets the aperture ; posterior margin raised above the edge of the 

 preceding whorl in an even spiral, not produced at its termination as in most 

 species of this genus ; surface covered with minute spiral threads, mostly paired, 

 the interspiices between the pairs usually wider than the threads and often wider 

 than the pairs, tlie width decidedly irregular; the axial sculpture of small equal 

 threads subequally spaced and crossing the spiral interspaces, but not overriding 

 the spiral threads; the reticulum formed is rectangular and does not give the 

 effect of punctation ; aperture somewhat wider in front, but not flaring, as in most 

 species of the genus ; outer lip thin, body with a thin callus extending on to the 

 pillar which is not gyrate and has no chink behind it ; axis not pervious ; anterior 

 and posterior parts of the aperture excavated. Lon. of shell, 33 ; max. diam., 

 16 mm. 



U. S. S. "Albatross," station 4G72, 88 miles southwest of Palominos Light, 

 Peru, in SSiS fathoms, infusorial ooze, bottom temperature 35°. 2 F. U. S. N. Mus. 

 110,563. 



This species is much thinner and even more cylindrical than S. gracilis Watson, 

 which is its nearest ally in the genus. 



Scaphander interruptus Dall. 



Plate 19, flffure 9. 



Scaphander interruptus Dall, Proc. U. S. Nat. Mus., 1889, 12, p. 297, pi. 12, fig. 12. 



U. S. S. " Albatross," station 2788, on the soutliern coast of Chile, in 1050 

 fathoms, mud, bottom temperature 37° F. ; station 2807, near the Galapagos 

 Islands, in 812 i'atlioms, ooze, temperature 38°. 1 ; station 3302, in the Pacific west 

 of tlie Gulf of Panama and nortliwcst of the Galap.agos Islands, in 1270 fathoms, 

 hard bottom, temperature at bottom 36°. -t F. U. S. N. Mus. 123,077. One of 

 tlie specimens obtained was living. 



Fragments were also obtained at station 3360, in 1672 fathoms, sand, tempera- 



