170 APPENDIX-PATELLID.E. 



gin entire, length 7'4, breadth 5*7, alt. 3 lines, (Mke. in Moll. Nov. 

 Holl. Spec., p. 34.) 



Western Australia. 



This is not P. insignis Dkr., a synonym of P. testudinaria. 



It is probably the same as Acmcea cruciata Linn. 



ACM^A ARANEOSA Gould. PL 73, figs. 90, 91, 92. 



Shell small, thin, rounded, slightly elevated, smooth, and without 

 ribs or sculpture ; apex nearly central, obtuse. Color pale yellow- 

 ish-green, reticulated with very fine rusty-brown lines, branching off 

 like rootlets towards the margin. The interior is whitish, with a 

 rusty ring just within the muscular impression ; the edge is sharp 

 and simple, and has a well-defined limbus, so thin as distinctly to 

 repeat the external linear markings. 



Length five-eighths of an inch ; breadth half an inch ; height 

 one-fourth of an inch. (Old.) 



A pretty little shell, most probably a Lotti, resembling some of 

 the species figured by Quoy, especially his orbieularis. Indeed it is 

 so like the reticulated variety figured in Quoy's pi. 71, fig. 33, that 

 the examination of a more extensive series might show them to be 

 identical. (Old.') 



iSooloo Sea. 



Patella (Lottia f) araneosa GLD., Proc. Bost. Soc. N. H. ii, p. 

 152 (1846) ; U. S. Exped. p. 347, figs. 450. 



PATELLA BARBARA Linne. (Page 96.) 



No locality is given in the text for this species. I am informed 

 by MR. GEO. W. TAYLOR that it is abundant at the Cape of Good 

 Hope. 



HELCIONISCUS REYNAUDI Desh. (Page 130). By a typographical 

 error this name is spelled incorrectly in the text. 



Family PATELLID^E. 



Dr. Thiele, in his continuation of Troschel's Das Gebiss der 

 Schnecken (received at Philadelphia since the publication of part 50 of 

 the MANUAL, in which my own classification of Patellidce was out- 

 lined), divides the family according to the characters of the radula 

 into groups as seen below. The great merit of Dr. Thiele's work 

 consists in his demonstration of the existence of a rhachidian tooth 



