OBSERVED AT MOGADOE. 177 



a (as figured e. g. in Sowerb. Conch. Man. f. 230) ; the blue rays 

 indistinct. Well represented in Y. H. Brit. Moll. t. 61. f. 3. 

 Transitional between a and /(3 (P. Icevis, Penn.). Length 8^-9, 

 breadth 6-6^ liues. 



Var. y, compressa, Lowe. — Shape and habit exactly of P. covi- 

 pressa, L. Vertex much further from the anterior margin than in a. 

 Shell strong, yet subpellucid, oblong, compressed, and deeper at 

 the sides than at each end, so that when placed on a flat surface it 

 rises or gapes considerably at each end, instead of lying flat, or 

 nearly so, as in a above described. One specimen, of a darker 

 coffee colour than the others, is distinctly radiated with blue dots 

 from the vertex. Length 10-14, breadth 7-8 lines. 



This seems to have much the same sort of relation to the Mogado- 

 rian P. pellucida, L., a, that P. pellucida, (3 (P. Icevis, Perm. ed. 1. 

 t. 90, lowest fig.), has to the English P. pellucida, L. The differ- 

 ences appear in both cases to be due only to age or position. P. pel- 

 lucida, y, having the sides deeper, from its station probably on 

 some stalk or cylindric surface. 



47. SipJionaria pectinata (L.), Patella pectinata, Linn., ed. 12, 

 1259 ; Hanley, Conch. Linn. 423, t. 4. f. 12 (not Born, Lam., &c.) ; 

 Lepas exigua qfricana, Mart. i. Ill, t. 7. f. 58, 59 ; Le Mouref, 

 Adaus. 84, t. 2. f. 5. 



My Mogadorian examjjles agree better with Adanson's than with 

 Hanley's figure. One of the two largest of them is 13 luies long 

 and 9^ broad ; the other 16 lines long and 12 broad. They are all 

 of a regular oval or oblong-oval shape, with the margin very even and 

 entire ; differing strikingly in this respect from 8. concinna, Sowerb. 

 Gen. f. 2, in which the margin is distinctly toothed or crenate. 



48. Hipponyx suhnifa, Sowerb. in Proceed. Zool. Soc. 1835, p. 5 ; 

 Pileopsis suhrufa. Lam. ed. L vi. 2. p. 18 ; Lepas conica riifcscens, 

 Martini, i. 146, 1. 12. f. 113. 



49. Fissurella reticulata (Don.), F. H. ii. 469, t. 63. f.4, 5=P. 

 grceca, Phil. i. 116 (not Linn. ov\j^vi\?^^P.europ(£a, Sowerb. Conch. 

 111. {Fissurella) 5. f. 43. — Shell strong, oblong, \\ith from fifty -five 

 to fifty longitudinal or radiating ribs, alternately large and small, 

 crossed at regular and equal distances by fourteen or fifteen con- 

 centric ribs, forming a regular and even network. 



50. Fissurella nubecula (Jj.) = F. rosea. Lam., Sowerb. = P. wm«- 

 hosa, Phil. i. 117 (not Linn.). 



52. Solarium luteum, Lam. ? Phil. i. 174, t. x. f. 27 ; Troclius 

 hyhridus, var., Chemn. v. L33, t. 173, f. 1704, 1705 (with reference 

 to Geve, t. 25. f. 24 a, b). Except the words " ad periphcriam bi- 



