28 ACM/EA. 



A. SUBROTUNDATA Carpenter. PI. 33, figs. 1,2, 3. 



Shell similar to A. filosa, but subrotund, more elevated, vertex 

 subcentral ; color more intense, the corneous lines closer, narrow ; 

 young shell paler, with two triangular rays posteriorly ; inside callus 

 livid, thinner. Length '53, width '45, alt. '15 inch. (Q>r.) 



Panama. 



Lottia sp. ind. a, C. B. AD., Panam. Cat. no. 368. Acmcea (f 

 floccata, var.} subrotundata CPU., P. Z. S. 1865, p. 277. 



I give figures of the type of this species, no. 15922 of the Smith- 

 sonian Institution collection. It is a subcircular shell, with the sub- 

 acute, erect apex near the center. The surface has sub-obsolete nar- 

 row, separated radiating threads. If held toward the light, fine close 

 unequal brown radiating lines are seen through it. The outside 

 appears of a dingy brownish, with obscure lighter lines. The inside 

 is bluish-white, with a chestnut spot in the cavity of the apex ; border 

 wide, dark, with close lines of dark brown. Length 13-}, breadth 

 11, alt. 4 mill. ; distance of apex from front end, 51 mill. 



In my opinion the A. vernicosa of Carpenter is a variety of this. 



A. VERNICOSA Carpenter. PI. 33, figs. 99. 



Shell small, subrotund, depressed-conical, apex situated at the 

 front two fifths of the shell's length ; whitish-green, ornamented here 

 and there with a few reddish-brown streaks ; sometimes with white 

 rays ; sculptured faintly with acute, radiating very distant lines, 

 sometimes obsolete; inside livid, callous, generally with a white 

 spatula; base subplanate, border narrow. (Cpr.) 



Length 7, breadth 5f alt. 2 mill. 



Panama. 



Lottia sp. ind. b, C. B. AD., Panam. Sh. no. 369. Acmcea (f var.) 

 vernicosa CPR., P. Z. S. 1865, p. 277. 



Had this form been brought from the China Seas it might have 

 been taken for A. biradiata Rv. From its solidity, however, its 

 rough exterior, and its callous interior, it appears to be adult. It is 

 barely possible that it may develop into A. vespertina. It differs 

 from the young of A. subrotundata in being much thicker and less 

 spotted with the green tint. (Cpr.) 



To Carpenter's description and remarks I add figures from the 

 type, in the Smithsonian collection. It is a small, yellowish form, 

 very solid, with erect, acute apex. I regard it as a probable variety 

 of A. subrotundata Cpr. With " vespertina " it has nothing to do. 



