. Elements of conchology / Prepared for the use of schools and colleges. Mollusks. EMARGINULA.—PATELLA. 61 passage to the air necessary for respiration, and also for the ex- pulsion of the excrements. 31. We give the name of Emarginula to mollusks very much like the Fissurellse, but their shell, in place of being open at the top, presents a slit or notch in front, communicating with the branchial cavity. OHBISH OF 32. The cyclobranch gasteropods closely approximate the pre- ceding, either in their general form, or in the disposition of their internal orga
. Elements of conchology / Prepared for the use of schools and colleges. Mollusks. EMARGINULA.—PATELLA. 61 passage to the air necessary for respiration, and also for the ex- pulsion of the excrements. 31. We give the name of Emarginula to mollusks very much like the Fissurellse, but their shell, in place of being open at the top, presents a slit or notch in front, communicating with the branchial cavity. OHBISH OF 32. The cyclobranch gasteropods closely approximate the pre- ceding, either in their general form, or in the disposition of their internal organs; but they are distinguished by their branchise being fixed around the edges of the mantle [fig- 78). 38. Some, the PatellcB {fg. 78), for example, are provided with a broad-based, conical shell, which covers the whole body ; they very much resemble the Fissurel- lee and Emarginulce, but the shell is not perforated at the apex, nor is there a notch in front as in the latter. The head is furnished with two pointed tentacles, having the eyes at their base, and a stout trunk; the anus is situate to the right, and a little above the head, and the branchiae are composed of m--. Fig. 78. PATELLA. leaflets or fringes, arranged in a row around the body, under the edges of the mantle. Patellae are found in almost all parts of the world ; they are found on rocks to which they adhere, and lie completely concealed beneath their shell, even after they are left bv the ebbino; sea. Explanation of Fin the edge of the shell the head. 78.—The animal of the patella seen from below;—c. -p. the foot;—m. the mantle ;—b. the branchiae :—t. 3L How does the genus Emargi'nula differ from Fissure'lla? (Emargi- nula, from the Latin, e, from, and margo, marginis, the margin—from the margin—notched.) 32. How are cy'clobranch ga'steropods distl'nguished ? (Cyclobranch, from the Greek, kuklos, a wheel, and bragchia, gills.) 33. What are the characters of the genus Pate'Ila ? (Patella, Latin,
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Keywords: ., bookcentury1800, bookdecade1840, booksubjectmollusks, bookyear184
