1884.] 'lightning' AND 'porcupine' EXPEDITIONS. 121 



Distribution. Arctic Norway southwards along the western coasts 

 of Europe to the ^Egean archipelago, Madeira {Watson), and 

 Teneriffe in the Canary Isles (McAndrew) ; 0-120 fms. 



Fossil. Pliocene : Norwich Crag, Italy. Post-tertiary : Norway 

 and Sweden, Scotland and Ireland, Rhodes ; 0-100 ft. 



This may be the Turbo albus of Adams (Trans. Linn. Soc.) and 

 Turbo albulus of Maton and Rackett, and if so, the first of those 

 names would take precedence of any other ; but they may be con- 

 sidered antiquated. R. rudis, R. nana, R. radiata, and R. granulum 

 of Philippi were erroneously given by me in my paper on the 

 Piedmontese Testacea as varieties of the present species ; that, 

 however, was nearly thirty years ago, and I have since seen all 

 these species instead of the descriptions of them. Morch united, 

 but wrongly as I believe, R. albella and R. sarsii with R. incon- 

 spicua as varieties. The sculpture is excessively variable, as regards 

 not only the number and comparative strength of the longitudinal 

 and spiral strise, but even their existence. Some specimens are 

 marked with one or two varices or larger ribs. The variety 

 variegata is pecuHar, and has been made a distinct species by 

 Schwartz v. Mohrenstern. 



i/ 27. RissoA DELiciosA ^ Jclfreys. (Plate IX. fig. /.) 



Shell conic-oval, rather thick, semitransparent, and glossy : 

 sculpture, short, sharp, and somewhat curved longitudinal ribs or 

 striae, of which there are from 16 to 20 on each of the three last 

 whorls, the first and second whoiis being smooth ; these ribs or 

 striae do not extend below the periphery ; they are crossed by more 

 numerous spiral striae or thread-like lines, the six lowermost being 

 much stronger than the rest ; this intercrossing, however, does not 

 impart to the surface a reticulated appearance, because the longi- 

 tudinal ribs are much thicker and less numerous than the spiral 

 striae : colour milk-white : spire short, bluntly pointed : whorls .5, 

 convex, gradually enlarging ; apex bulbous : suture deep : mouth 

 more round than oval, angular above : outer lip simple and rather 

 thin, but strengthened outside by a thickened rib : inner Up folded 

 over the pillar and forming with the outer rib a continuous or com- 

 plete peristome: base compressed or slightly concave, and having a 

 narrow chink behind the pillar-lip. L. 0'075. B. 0'05. 



Var. multicostata. Longitudinal ribs much more numerous, finer 

 and straight ; spiral striae also more numerous, but slighter and less 

 distinct except at the base. Some specimens have much more 

 delicate and close-set sculpture than is shown in the figures ; and in 

 other specimens the sculpture almost disappears. The variety, if it 

 can be properly considered distinct, is connected with the typical 

 form by intermediate gradations. Species-makers would revel in 

 this kind of manufacture. 



'Porcupine' Exp. 1870: Atl. St. 9, 13, 16, 17, 17a, 24, off C. 

 Sagres, 26-34, 36 ; Med. 50, Adventure Bank, .58. 



' Delightful. 



