MALENTOZOA. SESSILIA. 365 



This species is easily distinguishable by the longitudinal 

 stria? on its depressed areas. 



The above description is that of an individual presented to 

 me by one of my pupils, Mr. Alexander Mitchell, who found 

 it, in January, 1843, adhering to a shell, brought from deep 

 water. 



Balamis Candidas. Brown, Illustr. PL 6. f. 9, 10. 



GENLS 2. CLITIA. WART- SHELL. 



Shell orbicular, convex or subconical, depressed, ad- 

 hering by its base, and composed of four pieces, of which 

 two are very large, the operculum of two unequal valves, 

 and two small fixed valves. 



1. Clitia Verruca. Common Wart-ShelL 



Shell orbicular, depressed, convex, of two very large and 

 two small and little elevated valves ; all with large radiating 

 obtuse, transversely striated ridges, which are interlocked at 

 the margins and generally run out at the base, rendering it 

 angular ; the aperture large ; the operculum of two unequal 

 horizontal valves, striated in the same manner, and two smaller 

 fixed valves. Diameter two-twelfths of an inch. 



The form varies exceedingly, one or other valve being often 

 much enlarged, or sometimes almost suppressed, this arising 

 from the irregularities of the surface to which they are attached. 

 The base is membranous, and generally sunk considerably into 

 the substance of the calcareous body to which it adheres.. 



Very common on Pectens, Buccina, Fusi, and other shells, 

 as well as Crustacea, on all parts of the coast ; abundant in 

 deep water, off Aberdeen, Peterhead, Banif, and Portsoy. 



Lepas Verruca: Gmel. Syst. Nat. 3212. Lepas striata. Perm. 

 Brit Zool. iv. 73. PI. 38. f. 7. Lepas intertexta. Donov. Brit. 

 Sh. I. PL 3b'. f 1. Balanus striatus. Mont. Test. Brit. 12. 

 Lepas striatus apertura obliqua. Walker, Test. Min. Rar. f. 87. 

 Creusia Verruca. Larak. Syst. v. 400; Ed. 2. v. 671. Creusia 

 Verruca. Brown, Illustr. PL 7. f. 30. Clitia striata. Leach, En- 

 cycl. Brit. Suppl. iii. 171. 



GENUS 3. CETOFIRUS. WHALE-BARNACLE. 



Shell hemispherical, formed of six pieces, and pre- 

 senting six elevated, longitudinally silicate areas, and an 

 equal number of intervening depressed minutely striated 



