186 A. K Verrlli — Mollusca of the New England Coast. 



Family SEGUENZID^. 



The beautiful deep-sea shells included in the genus Seguemia., ^nth 

 the closely allied forms [Basilissa, etc.), present several remarkable 

 characters which ought, certainly, to entitle them to rank as a dis- 

 tinct family. 



The shell is trochiform, with elegant revolving and transverse 

 raised sculpture, and usually translucent, with more or less pearly 

 luster, when fresh. Umbilicus open or closed. Aperture irregular, 

 usually with a marked posterior sinus, a short or rudimentary canal, 

 or anterior sinus, and sometimes with two anterior sinuses. Oper- 

 culum thin, rounded-ovate or ear-shaped, with a subcentral nucleus 

 and fine concentric lines. Jaws ovate, with tesselated surface and 

 denticulated edge. Odontophore (in Segxienzia) minute, Tcenioglos- 

 sate/ the central tooth small, with one denticle ; the inner laterals 

 smaller, with ciirved unarmed tip; the two outer laterals slender, 

 sharp, strongly curved. 



By Jeffreys this group was placed near kiolariimi (Ptenoglossa) ; 

 by Watson in the Trochidm (Rhiphidoglossa). 



It has really no affinity with either of those groups, but belongs to 

 the Tmnioglossa. It seems more nearly related to Aporrhais and 

 allied forms, than to any of our other shalloAV water groups. 



Seguenzia formosa Jeffreys. 



Jeffreys, Proc. Roy. Soc. London, vol. xxv, pp.200, 201, 1876 (wood-cuts); Ann. 



Mag. Nat. Hist., p. 319, April, 1876. 

 Boog "Watson, Molhisca Chajlenger Exp., Part III, Journ. Linn. Soc, vol. xiv, p. 



587, 1879. 



Plate XXXI, figures 14, 14o. \lh. 



Several living specimens were dredged by the Albatross in 1883, 

 in 1290 to 2033 fathoms. Station 2037, N. lat. 38° 53', W. long. 69° 

 23' 30", in nsi fathoms, one young specimen (No. 38,232) ; station 

 2038, N. lat. 38° 30' 30", AV. long. 69° 08' 25", in 2033 fathoms, two 

 living specimens (No. 38,078) ; station 2084, N. lat. 40° 16' 50", W. 

 long. 67° 05' 15", in 1290 fathoms, two living specimens (No. 38,247). 



These specimens sliow some variation in sculpture and in the 

 presence or absence of a small umbilical perforation or channel. 



In the typical form of formosa the body-whorl is surrounded by 

 three principal carinas, Avhich are prominent and rather sharp. One 

 of these, around the periphery, is coincident with the posterior angle 

 of the aperture, and, therefore, with the suture, which it usually con- 



