108 
Petricula Lmk. 
P. divaricata Ch. station: in crevices on madrepores; 
St. Thomas; Virgin-Isl; Swift! remark: Swift says it 
distinguishes itself by purple syphons from P. lapicida 
Ch., which has yellow syphons; see P. lapicida Ch. vol. 
10 tab. 172 fig. 1666—67, Woods Ind. test. pl. 8 fig. 
73, Sowb. Tes. pl. 146 fig. 24—25. 
P. lapicida Chem. (Venus Chem., P. costata Gray & Lmk., 
P. divaricata Chem. , Ven. divergens Gm., Pr. lucinalis 
Lmk.) station: in crevices on dead madrepores; ha- 
bitat: Australia; Sowb.! St. Thomas; Swift! Krebs! St. 
Domingo; Cuba; Martinique; dOrb.! Antillae; Mérch! 
remark: we have a large number of specimens , but 
are not able to distinguish the shells of P. div. & lap.; 
Swifts remark about the syphons (see P. div.) are very 
interesting, but perhaps the colour of the syphons varies 
by the same species. 
P. pholadiformis Lmk. station: — ? — ; habitat: 
United States; Cuba; d’Orb.! 
P. roccellaria Lmk. station: — ? — ; habitat: St. 
Thomas (by J. H. Newton); Jamaica; Ad.! 
P. typica (Chloristodon) Jonas. station: in crevices and 
holes in Madrepores on 2 to 10 feet water; habitat: 
Antillae; Moérch pg. 20! Virgin-Islands; Swift! 
Anatinacea. 
Periploma Schum. 
P. ineqvivalvis Schum. station: — ? —; habitat: 
Marie Galante; Beau pg. 25! 
Thracia Leach. (Blainy. 1824). 
T. rugosa Conrad. station: —? —; habitat: Rio Ja- 
neiro; d’Orb. ! 
