LIST OF PLATES. 3 



A. Ad. ; the long specimen has grown in the burrow of a Ldthophagus, 

 and displays margin-layers at the umbonal region, and one Lessonioid 

 lamina in front ; p, profile of the last-named specimen, with deck promi- 

 nent, and back somewhat indented, as in C explanata, Gld. 



Fig. 2. Young state of Crejndula unyuiformis. Lam. {lanacus, H. & A. Ad.), to com- 

 pare with the last species, which it closely resembles when adolescent : a, 

 inside view, showing large imbedded spiral portion ; b, outside, showing 

 flattened, smooth spire. 



Fig. 3. Crepidula aculeata, Gmel,, including Calyptrma echinus, Brod., Calyptrma 

 hystrix, Brod., Crepidula Calif ornica, Nutt., and probably Crepidula 

 costata, Mke. (not Shy.), subgenus Crepipatella, H. & A. Ad. •. a, young 

 state, like Neritina, deck just commencing; b, ditto, a stage older j c, the 

 same in profile ; d, ditto, somewhat older ; e, ditto, a little older ; /, out- 

 side view, older, showing spiral growth, margin not produced, spines just 

 appeai-ing; g, a group of deck-margins, arranged as in fig. If, the three 

 to the right being magnified ; the second from the left is the normal state ; 

 in the first, not only the characteristic medial angle is rounded off, but an 

 abnormal angle appears, turned the wi-ong way ; h, two specimens, out- 

 side view, to show straight and spiral growth, as in fig. \ o; i, two speci- 

 mens, laid with the upper mai-gins corresponding, to show dispropor- 

 tionate length of deck ; the short deck belongs to the dotted margin ; 

 j, two specimens in profile ; one arched, with deck internal ; the other 

 (dotted) flat, with deck prominent. 



Fig. 4. Lophyrus articulatus. Shy. : a, front profile of a specimen abnormally tri- 

 lobed ; the dotted line shows the same profile of an elevated specimen ; 

 b, terminal valves of two specimens, one with inner margin incurved, the 

 other excurved ; c, medial valves of two specimens, one much waved, the 

 other nearly straight. These characters are much dwelt on by Midden- 

 dorfi^ in the discrimination of species. 



Fig. 5. A monstrosity of Fissurella virescens. Shy., inside view, with a circular hole 

 in addition to the normal one. 



PLATE IX. 



Fig. 1. Crucibulum imbricatum, Sby., Brod., Desh. =:P«feKa scutellata, Wood,= 

 Calypeopsis rugosa. Less. nonDesh. : including the non-pitted form, Dys- 

 potcea d-entata, Mke.=-Calyptraa 1 extinctorium, Sby. non Lam. = 00- 

 lyptrcea rugosa, Val., Rve., non Desh. : showing development, a, try, 

 magnified, outside view ; b, ditto, inside, shell like Narica, with umbilical 

 chink, slight columellar lip, and a thin film of patelliform margin sur- 

 rounding the whole; c, young state, slightly magnified, cup much ex- 

 panded; in this state it appears to belong to the subgenus Dispotcea (Say) 

 of H. & A. Ad.; d, ditto, outside view, ribs scarcely indicated; e, 

 adolescent, ribs strongly developed, cup-angle narrower ; /, a stage nearer 

 maturity, cup-margins nearly closed ; g, adult state. 



Fig. 2. Crepidula Idorsata, Brod., var. bilobata, nearly adult (Crepipatella dorsata, 

 H. & A. Ad.), to compare with^^r. 1 c and 3 a. 



Fig. 3. Crucibulum spinosum. Shy., ^^ Patella Peziza, Wood,=z Calyptresa tubifera, 

 hess. ,= Calypeopsis auriculata, D'Orb. non Chemn. ; including Calypeop- 

 sis tenuis, C. hispida, and C. maculata, Brod. The C. quiriquina, Less.= 

 C. Byronensis, Gray, MS.=C rugosa, D'Orb. (pars), is probably a coarse 

 variety of the same species ; and the C. rugosa, Desh., non Less, nee Val. 

 =:C. lignaria, Brod., may be a distorted growth of the same variety. 

 a, young state, magnified ; b, the same, a stage older, wrinkles developed 

 crenating the margin, shape abnormal ; c, inside of smooth form, adult ; 



d, a specimen with the cup diseased, probably owing to the decay of half 

 the outside, where the commencement of the cup may be seen exposed ; 

 margin of the undecayed part thick and in layers, as in C. quiriquina ; 



e, outside view of specimen without spines, wrinkles very faint ; /, speci- 

 men with a very few rudimentary spines in the form of tubercles, and 



