MOLLUSC A OF PORTO RICO. 
449 
Subfamily FISSURELLIDIN^E. 
Genus LUCAPINELLA Pilsbry, 1890. 
Shell oblong, depressed, narrowed in front, cancellated; apex with a large opening, which is 
margined within by a strong, entire, nontruncate border. The shell characters are essentially the 
same as in Fissurella, the differences between the two genera being mostly anatomical. 
Type, Clypidellci callornarginatct Carpenter. 
Lucapinella limatula Reeve. 
Fissurella limatula Reeve, Conch. Icon., Fissurella, fig. 115, 1850. 
Shell oblong, narrowed and rounded in front, depressed, the summit subcentral, with a large 
opening of the same shape as the shell; surface sculptured with alternately larger and smaller radiating 
ribs; sometimes there are two or three small ribs between the larger ones, and all are crossed by 
regular concentric laminae which rise into erect scales over the ribs; white or rayed with ashen purple 
or blackish. The callus around the opening is heavy and continuous. 
Length, 26; breadth, 15; height, 6 mm. 
Catano; Mayaguez Harbor, Porto Rico. 
One specimen of the dimensions given above came from the former locality. 
Genus LUCAPINA Gray, 1857. 
Shell oblong oval, embedded in mantle but covering most of the animal; apex in front of middle, 
having a large oval perforation; edges of shell not thickened, regularly and finely crenulated. 
Section CHLAMYDOGLYPHIS Pilsbry, 1890. 
Lucapina adspersa Philippi. 
Fissurella adspersa Philippi, Abbild. und Beschr., ii, p. 34, pi. I, fig. 3, 1845. 
Shell oblong, depressed, conical, narrower in front, the sides a little convex, the apex in -front 
of the middle of the shell; surface sculptured with radiating, alternately larger and smaller ribs, which 
are crossed by strong, concentric, regular ridges; perforation oval, much the shape of the shell; inner 
border strongly crenulate, the teeth arranged in pairs; callus strong, swollen, truncated behind, and 
having a greenish streak along each side. Color whitish or pale brownish, with from seven to nine 
broad rays of darker' color; bluish white within, showing the rays. 
Length, 21; breadth, 11; height, 5 mm. 
San Geronimo, one shell, not adult. 
Lucapina cancellata Cowerby. 
Fissurella cancellata Sowerby, Conch. 111., fig. 29, 1839. 
Shell oblong, scarcely narrowed in front, low conical, sculptured with numerous radiating ribs 
which are alternately larger and smaller, and strong, regular, concentric threads, which form flattened 
nodules where they cross the ribs; orifice rather large in front of the middle, long oval, stained 
blue black; inside white, the callus bluish black, slightly truncate behind. Color white throughout 
or faintly rayed or decked with brown. 
Length, 25; breadth, 15; height, 7 mm. 
One bne alcoholic specimen was obtained from the reefs at Ponce. 
Subfamily EMARGINULIN/E. 
Genus FISSURIDEA Swainson, 1840. 
Shell ovate, conical, the oridce in front of the middle; apex spiral, inclined backward when 
young; surface cancellated; internal opening having a strong callus within, which is truncated behind 
or has a pit. The shell characters of several of the genera of the Fissurellidx are not well differen- 
tiated, the classification being based largely on the anatomy. 
Fissuridea listeri d’Orbigny. 
Fissurella listen d’Orbigny, Moll. Cubana, ii, p. 197, pi. xxiv, figs. 37-39, 1845. 
Shell solid, conic, moderately elevated; sides nearly straight; sculpture consisting of radiating 
ribs which -are alternately larger and smaller; sometimes there are three sets of them of different sizes; 
P. C. B. 1900—29 
