JEFFREYS! A. 61 



close together, and surrounded bj pale rings ; they are visible 

 only through the shell: foot large, triangular, bilobed, and 

 slightly auricled in front, bluntly pointed behind. 



Shell oval, extremely thin, semitransparent, highly glossy 

 aud of an opaline lustre : sculptiwe as in the last species : colour 

 bronze or dark honicolour when the shell is living or contains 

 the remains of the animal, yellowish when it is empty : spire 

 short, with an abrupt and blunt point: ivliorls 3|, swollen, 

 rapidly enlarging ; the last occupies at least three-fourths of 

 the spire, and the first is mammiform : suture broad and deep : 

 mouth oval, capacious, and more than half the length of the 

 spire : outer lip sharp and thin, incurved above, slightly an- 

 gulated and expanding below : inner lip flexuous and thick- 

 ened on the lower part of the pillar, behind which it forms a 

 narrow umbilical chink : operculum similar to that of J. dia- 

 phana ; but the sj)ike or apophysis is slightly curved, and oc- 

 casionally double, so as to make two separate leaves. L. 0-1. 

 B. 0-075. 



Habitat : Guernsey and Sark, in rock-pools among 

 Corallina officinalis (Barlee) ; Falmouth (Cocks and 

 Barlee) ; Cumbrae, Clyde district (Norman) ; Skye (A. 

 M^Nab) ; Wlialsey Skerries,, Shetland^ on Laminaria 

 saccharina, a little beyond low-water mark (J. G. J.). 

 Altliough very local^ it is abundant. I found a single 

 specimen at Lerici ; and Verany has recorded this species 

 from Nice. 



At the Whalsey Skerries it especially frequents a 

 sheltered part of the sound, close to a fish-curing station, 

 wdiere the oftal is thrown out. The other species of 

 Jeffreysia and Trochus helicinus are its companions. Do 

 all these feed on decaying animal matter, or on Infu- 

 soria produced from it ? The spawn is deposited on 

 leaves of the Laminaria ; it is of a semioval shape, with 

 a large hole in the middle. When ripe it forms a thick 

 mass, and contains an immense number of yellowish 

 unispiral shells which are agglutinated together by a 

 gelatinous matrix. The adult shell resembles Hydrobia 



