1885.] 'lightning' and 'porcupine' expeditions. 43 



over the spiral ridges, a nodose or tuberous appearance is caused by 

 their intersection ; the base is covered with dehcate and close-set 

 spiral striae ; apex smooth : colour pearly white : suture slight : 

 spire short, turreted : whorls 5-6, convex ; the last occupies three 

 fourths of the shell ; the first or topmost whorl is bulbous and 

 intorted : mouth large, polygonal, irregularly sinuated at its base ; 

 outer lip thin and prominent : fssure placed a little below the 

 suture of the last whorl ; it is broad, deep, and ends in a curved 

 indentation : inner lip none : pillar semicircular : umbilicus narrow, 

 but distinct and deep-margined outside, and defined by a slight 

 ridge or keel which terminates in a sharp and projecting point. 

 L. 0-125, B. 01. 



'Porcupine' Exp. 1870: Atl. St. 16, 17, 17a. 



Distribution. Bay of Biscay (' Travailleur ' Exp.). 



Not S. e?-itima of Verrill, judging from the description and 

 figure. 



3. Seguenzia tricarinata\ Jeffreys. (Plate V. fig. 2.) 

 Shell globose, very thin and fragile, transparent, and of a glassy 



lustre : sculpture, three spiral thread-like striae or keels on the body- 

 whorl, viz. one encircling the periphery, another at a short distance 

 below it, and a third at a somewhat greater distance above the peri- 

 pheral stria ; the penultimate whorl is marked with a similar stria, 

 a little above the suture ; the next whorl is keeled at the top : colour 

 whitish : suture deep : spire short and compressed : whorls 3-4, 

 convex ; the last is disproportionally large ; apex flattened : mouth 

 roundish, angulated at the base : outer lip thin ; fissure wide but 

 shallow, forming an angular indentation : inner lip filmy : pillar 

 gently curved and thickened : umbilicus narrow and shallow, mar- 

 gined outside by a slight but distinct semicircular stria or keel. 

 L. 0-075, B. 0-075. 



'Porcupine' Exp. 1870: Atl. St. 17a. A single but character- 

 istic specimen. 



Distribution. Off C. Verd. I. ('Talisman ' Exp.) ; 1192 fms. 



4. Seguenzia carinata, Jeffreys. (Plate V. figs. 3, 3 a.) 



8. carinata, Jeffr. Proc. R. S. 1876, p. 201 ; Ann. & Mag. Nat. 

 Hist. 1877, p. 320. 



• Porcupine ' Exp. 1870 : Atl. St. 16, 17a, off C. Espichel, 22. 



Distribution. North Atlantic (' Valorous' Exp.), off Fayal, Azores 

 (' Challenger' Exp.), off Marocco, Sahara, C. Verd. 1., and Azores 

 (' Talisman ' Exp.) ; 681-2199 fms. 



This species has a labial slit as in the typical species S. formosa. 



5. Seguenzia reticulata, Philippi. 



Solarium reticulatum, Phil. Moll. Sic. ii. p. 149, t. xxv. f. 6. 



'Porcupine' Exp. 1870: Atl. St. 9, 16, 17, 17a. 

 Distribution. Coast of Portugal ('Travailleur' Exp.), off Ascen- 

 sion I., and Culebra I. (' Challenger' Exj).) ; 390-1791 fms. 



1 Having three keels. 



