TRIBE MYTLIACEA. 253 



P. Muricata. Lam. 8 .—Lin. Sys. 1160?— D. p. 32%.—Knorr. 



6. t. 20./. \.— fV. t. 12. f. d. — Ch.f 781. badly .—List . t . 370./. 

 210. Thin, pellucid, pale fulvous, subtruncated, the longitudinal 

 sulci few and muricated : the scales small erect and somewhat 

 acute; posterior side unarmed. Atlantic, Antilles. Moderately 

 large* 



P. Pectinata* Lam. 9. — D. p. 325. — Lin. 11 GO ? — Turt. Biv. 

 t.\9.f. \.— W, t. 12. /. 4.—Phil.p, 74.— Gualt. t. 79. A.— Mont, 

 p. 178 Triangular-oblong, horncoloured, with numerous radiating 

 elevated narrow sulci (except on the ventral side which is merely 

 roughened by the crowded layers of growth) which are often armed 

 with very small distant concave scales ; dorsal edge straight, the 

 longer, angulated at the subtruncated anterior base ; ventral edge 

 elongated, incurved towards the beaks, elsewhere nearly straight. 



7. N. Europe. The specimen in Linnaeus's collection much more 

 resembles Inflatus than this our British Species. 



P. Saccata. Lin. 1160. — D.p. 333. (partly) — Lam. 10. — Leach 

 Z. M. 1. t. 51.— Rump. t. 46./. N.--V. Nuttalii. Con. J.A.N.S. 

 Phil. 7. t. 19 /. 4. Satchel shaped, subquadrate, smooth: thin, 

 horn coloured, the disk with about five prominent broad undulating 

 unarmed ribs ; posterior ventral edge incurved, anterior base sub- 

 truncated. 8. — Amboyna, fyc. 1 



P. Varicosa Lam. 11. — Seba. 3. t. 92. (the two penult side /.) 

 Semitransparent, not spinous, reddish rufous, obliquely rounded 

 at the anterior ventral margin ; with thick waved varicose radiating 

 ribs : a cloudy blackish brown spot towards the base of its poste- 

 rior side. 8. — Isle of Trinity. M. Deshayes remarks "Should the 

 existence of this -species, depend on the authority of Stba'sfgures, the 

 species must be expunged, as Seba has represented a variety of 

 Rudis.'' 



P. Bicolor. Chem.f. 780. (distorted)— W. t. 13. f 14. (copy of 

 Ch.)—D. p. 330. — P. Dolabiata. Lam. 12. Moderately ventri- 

 cose, elongated, imbricated and lamellar near the anterior ventral 

 margin which is obliquely rounded, with obsolete longitudinal sulci ; 

 greyish rayed with smoky brown, semitransparent ; anterior margin 

 very long, straight and subacute. South Seas. 14. — Australia. 



P. Ingens* Pen. 4. p. 115. — Mort.p. 180. and Sup. p. 72. — 

 Lam. 13. — D. p. 325. — Turt. D.p. 148. — P. Ingens and Fragilis 

 Turt. B.p. 222. t. 20. f 1, 2.— P. Ljevis. Bon. t. 152. Ovate- 

 triangular, moderately long, more or less rugged, with very narrow 

 distant unarmed (except when very young) radiating ribs which be- 



1 We have given a copy also of Chemnitz's Saccata W. t. 13. /. 

 18. which is undoubtedly distinct from this and more like Conrad's 

 Semicostata. 



