588 THE VOYAGE OF H.M.S. CHALLENGER. 



Fossil. — From the Pliocene of Calabria, the Pleistocene of Sicily, and the recent clays 

 of both (Seguenza). 



Dr Gwyn Jeffreys (Brit. Conch., vol. iv. p. 37) says he regards this as a small variety of Rissoa 

 costulata, Alder, a view I entirely share, with the addition that I believe both these and a great 

 many other species, British and foreign, to be mere varieties of Rissoa parva, Da Costa. Perhaps, 

 when all zoological classification has been reduced to chaos, and each museum specimen has received 

 a separate name, a real revision of species will be entered upon. In the meantime such labour is 

 thrown away, and Scacchi's species has as much right to recognition as the others around it. 



4. Rissoa pyrrhias, 1 n. sp. (PI. XLIV. fig. 4). 



Station 24. March 25, 1873. Lat. 18° 38' 30" N., long. 65° 5' 30" W. Off Culebra 

 Island, West Indies. 390 fathoms. Pteropod ooze. 



Shell. — Strong, oval, pointed, conical, broad, continuously ribbed, glossy, translucent 

 white, with a slight marginated suture, flat minutely subscalar whorls, and an oval pointed 

 externally varixed mouth. Sculpture : Longitudinals — there are on each whorl about 

 13 strong straight distant rounded ribs, which are coutinuous from whorl to whorl, though 

 cut off by the suture below which each rises suddenly in a well-marked triangular bluntly 

 pointed tubercle ; they cease almost abruptly on the base ; the last forms a strong labral 

 varix ; there are faint lines of growth. Spirals — on the upper part of the whorls there 

 are very faint traces of spiral threads ; on the base are five or six broadish but feeble 

 threads. Colour translucent white, with a brilliant surface. Spire broadly conical, 

 slightly subscalar, from the prominence of the subsutural tubercles. Apex: the 2| 

 embryonic whorls are small and subcylindrically globose, with the small rounded tip 

 slightly prominent ; they are tawny yellow, and are scored with coarse but feeble spiral 

 threads. Whorls 6, flatly conical, of rapid increase. Suture linear, slightly impressed 

 and submarginated by the costal tubercles. Mouth large, ovate, pointed above, a little 

 oblique. Outer lip bevelled off to a thin edge, strengthened by a strong external varix, 

 very patulous on the base. Inner lip thin, but defined on the body, thin and prominent 

 on the pillar, where it has a minute umbilical furrow behind it. H. 0-115 in. B. 0'07. 

 Mouth, height 0-045, breadth 0"041 



A good deal like Rissoa xanthias, Wats., and Rissoa amhlia, Wats., which see for the differences. 



5. Rissoa xanthias, 2 n. sp. (PI. XLIV. fig. 5). 



Station 24. March 25, 1873. Lat. 18° 38' 30" N., long. 65° 5' 30" W. Off Culebra 

 Island, West Indies. 390 fathoms. Pteropod ooze. 



Station 122. September 10, 1873. Lat. 9° 5' S., long. 34° 50' W. Off Pernambuco. 

 350 fathoms. Red mud. 



1 Tiw/aj, red^head, from its coloured apex. 2 %av6ixg, yellow head. 



