292 MAZATLAN UNIVALVES 



this form are sometimes seen faint radiating ribs, which are 

 quite abnormal, and are perhaps due to the inconvenient shape 

 into which the creature finds itself driven.* 



• A3 D'Orbigny seems to have confounded both species and synonyms in this 

 family, the following account of his type specimens in the Br. Mus. (mostly dead 

 Bhells) may be useful to students. His onn names and synonyms are given in 

 quotations : the numbers are those on the tablets. 



559,560, " C. rugosa = imbrioata. Sow." are the true Crncihulum imbricatum ; 

 not C. rngosa. Desk. 



661, "C. rugosa, D^sA. = tenuis, Brod." is neither one nor the other; but = 

 C. ? imbricatum, var. Broderipii, Froc. Zool. Soc. June, 1856. 



656, "C. rngosa, Desh. ^= rudis, Brod." is neither ; but appears the shell described 

 in Proc. loc. cit. as C. ?? imbricatum, var. Cumingii. 



583, "C. tubifera, Xess. = spinosa, Sow. ^ aurienlata, CAfTB." is the true Cruci- 

 bulum spinosum; but quite distinct from Patella auriculata, Chem. which 

 appears to be the W. Indian form of C. umbrella, Desh. = rudis, Brod. 



555, "C. quinquina" is the dull, thick, spineless ? variety of Crucibulum spinosum, 

 =:Byronensi3, Gray. 



o57, "C. rugosa, Desh." is an interesting intermediate form between the last and 

 the next, of the shape of Scurria mitra. Less. Sf Each., and sometimes develop- 

 ing a very few ribs . 



658, "C. rugosa = lignaria," rightly named; the extreme form, like the large 

 fossil Hippouyx. 



666, "C. intermedia" is a Galerus, apparently distinct from any of Broderip's 

 species. 



665, "C. mamillaris, & C. lorica [Plichen] Brod." is not the Galema mamillaris, 

 but the Galerus unguis, Brod. 



667, "C. pilcolus" intermediate in character between Galerus and Trochita. 



- - - , "C. Patagonica" is probably a variety of Crepidula dilatata ; as also may 

 be - - - , "C. foliacea", in spite of its rugose surface. 



673, "C. protea" are probably dead specimens of Crepidula incurva, or C. onyx, 

 or both. 



674, "C. protea" are perhaps C. nivea, as may be some of the specimens of C. 

 Patagonica : but, along with the last, are too much worn for certain identification. 



The following additional particulars of Air. Brooerip's species may also be use- 

 ful to students. 



Crolcrut unffuit is very small, conical, and dark coloured. G. sordidua appears 

 a flatter, lighter variety of the same species. Mr. Cuming's specimens are all 

 jovered with Bryozoa ; but none of them shew any tendency towards the corruga- 

 ted exterior represented in the Trans. Zool. Soc. pi. '2S, f. 2. 



Cfalerus ttriatut is well distinguished by its strongly sculptured exterior. 



Orepidula mari^nalii is intermediate in characters between C. onyx and C. 

 aculeate; having the external appearance of the former, with a thin waved deck 

 more resembling the latter. 



Orucibulum terraium outside resembles Cr. ?? imbricatum vir. Cumingii: but 

 within, it has a remarkably appresscd and angular cup. It comes more close to 

 Or. pectinatum, Proc. Zool. Soc. June, 1356. 



