CORONULA. 



TESTA suborbicularis, obtuso — Vel compresso- 

 conoidea, valvis senis, inaequalibus, lateraliter 

 ferruminatis, valvam indivisam simulantibus, 

 composita : extremitate inferior e truncata, affixa ; 

 superiore operculo quadrivalvi membranisque 

 clausa : valvis operculi laevibus, oblongis, ob- 

 tusis : parietibiis crassissimis, intus plerumque 

 cellulis radiantibus, excavatis. 



Separated from the Balani of Bruguiere by Lamarck, 

 on account of the peculiarities of its structure, although 

 the number of valves of which the shell itself is formed, 

 as well as its operculum, accord precisely with Balanus; 

 the same reasons might have induced us to separate the 

 species commonly called Lepas testudinaria from the other 

 Lamarckian Coronulce under another generic appell|^tion, 

 (which some conchologists have done,) had not the pau^ 

 city of species seemed to render such a separation unne- 

 cessary. It must not, however, be forgotten, that on 

 account of the different situations in which they occur, 

 there is one very essential difference between the Balani 

 and the Coronulce, the latter being destitute of the shelly 

 base by which the former are attached. 



Shell suhorbicular, sometimes nearly cylindrical, but 

 more commonly of an obtuse or very compressed conical 

 form, composed of six unequal, laterally soldered valves, 

 having the appearance of being one piece; lower extre- 

 mity truncated, attached; upper closed by the operculum 

 consisting of four valves and their membraneous attach- 

 ments. Valves of the operculum smooth, oblong, obtusely 

 terminated. vSides of the shell very thick, their sub- 



