82 BRITISH TUN1CATA. 



Body ovate or subgiobose, of a pinkish hue tinged 

 with lilac, attached by a broad base. Aperture* a little 

 apart, rather large and conical, but not much produced ; 

 the branchial terminal, the a trial nearly so, each 

 margined and rayed with violet. Test tough, smooth 

 or slightly mamillated, covered with small scaly plates 

 [which are marked with concentric lines], silvery in- 

 side. Mantle very thin and delicate, transparent, pale 

 rose-coloured, with fine longitudinal muscular fibres 

 crossed by irregular transverse ones. Tentacular fila- 

 ments slender, simply pinnate. Branchial sac bright 

 rosy orange, with six folds on each side. Ovaries 

 forming a double, linear, perpendicular series of 

 yellowish-white globular masses on each side, with a 

 fimbriated mass of dark reddish sperm-cells between. 



Diameter from half an inch to an inch. 



Hab. On shells, etc. (dredged in about 15 fathoms 

 at Guernsey). 



ENGLAND. Hastings, Sussex (Bowerlnrnk). Lulworth 

 (Jove, Dorset (Jeffreys}. 



SCOTLAND. Shetland (Jeffreys). 



IEELAND. - -Birterbuy Bay, Connemara, Galway 

 (Brad//). [See also p. 81.] 



CHANNEL ISLANDS. Guernsey (Alder). 



First record. Alder, 1863 ; "coll. 1853. 



The test (PL XXX, fig. 3) though tough and hard 

 is not very thick ; the scales covering it vary in size 

 and shape and are many-sided. In old specimens they 

 are occasionally a little elevated, giving to the surface 

 a mamillated appearance ; they form a complete pave- 

 ment, the margins lying in close contact. 



The mantle (PI. XXXII, figs. 1 and 2) is delicate 

 and adherent to the test; the longitudinal muscular 

 fibres are placed considerably apart, and radiate in 

 regular order from the apertures ; the transverse fibres 

 are delicate, and are less-regularly disposed. The 

 inner surface of the mantle is peculiar for the vast 

 number of minute fleshy nodules which clothe it, and 



