18 ORDER I. SESSILES. 



gradatim minores confertim co-ordinatis. Operculum bipartitum, 

 valvis quatuor anticis majoribus corapositum. 



Not having had the opportunity of examining this rare and peculiar 

 Lepas, we give verbatim the description of Sowerby, by whom it was 

 introduced. "Like Octomeris, the shelly cone immediately surround- 

 ing the animal consists of eight pieces, and its operculum is also com- 

 posed of four ; here, however, the resemblance ceases. The peculiarity 

 of the present genus consists in a number of narrow perpendicular valves 

 arranged around the above-mentioned shelly cone, and in rows like 

 pales, the first row of which consists of eight pieces, placed so as exactly 

 to cover the sutures of the cone immediately surrounding the animal : 

 around this, are then placed several sets of more and more numerous 

 pieces, gradually decreasing in size, so that the outer row, which is most 

 numerous, consists also of the smallest pieces, the additional rows seem- 

 ing to be produced as the animal increases in age." 



Example. 

 PL IV. Fig. 1 to 6. 

 Catophragmus imbricatus, Sowerby, Genera of Shells, No. 28. 



OCTOMERIS, Sowerby. 



Testa subconica, valvis octo ineequalibus lateraliter conferruminatis com- 

 posita ; apice pervio, operculo valvis quatuor composito, anticis 

 majoribus. 



This is another peculiar variety of Lepas introduced by Sowerby, 

 whose shell, as its name implies, is composed of eight pieces, closed 

 together at the sides, and distinguished by their internal sutures and 

 foliaceous structure. In this character it differs essentially from the 

 shell of Balanus, as also in having no testaceous base. The operculum 

 is composed of four pieces, of which the anterior pair are the larger. 



