364 
BULLETIN OF THE UNITED STATES FISH COMMISSION. 
Length, 40; diameter, 23 mm. 
Arroyo; San Geronimo; Boqueron Bay; Aguadilla; Guaniea; Porto Real; Ponce, Porto Rico. 
The distinctions between this form and B. striata Brug. of the Mediterranean region are faint and 
somewhat inconstant. As a rule, amygdala is more inflated and has a smaller umbilicus at the vertex 
than striata, but this is not always the case. The striata is more apt to have revolving lines at the 
vertex and microscopic spiral lines on the body than amygdala, but specimens of the former occasion- 
ally exhibit these characters. 
Family AKERATID4}. 
Genus HAMINEA Leach, 1847. 
Shell thin, fragile, unicolored, yellowish or greenish, globose, ovate or subcvlindric; vertex 
concave, imperforate or minutely perforate; aperture as long as the shell, narrow above, wider below; 
umella concave, thin, showing a slight fold where it joins the body of the shell. 
Type, Bulla hydatis Linnfeus 
Haminea elegans Gray. 
Balia elegant Gray, Ann. of Philos., new ser., ix, p. 408, 1825. 
Balia guildingi Swainson, Mai., pp. 251, 360, fig. 46, 1840. 
Shell roundly oval or subcvlindrical; surface with irregular growth lines, and showing plainly 
close, spiral striation, which is usually straight but sometimes a little wavy; vertex concave, narrowly 
and deeply perforated, the outer lip rising from the left side of the perforation; outer lip well arched, 
rounded above and below; columella deeply arcuate; parietal callus thin, encircling the perforation at 
the vertex. Color brownish or greenish yellow, lighter above and below. 
Length, 19; diameter, 13 mm. 
One broken specimen in fresh condition was taken at Mayaguez Harbor, Porto Rico. 
Haminea succinea Conrad. 
Bulla succinea Conrad, Proc. Acad. Nat. Sci. Phila., in, p. 26, pi. 1, fig. 5, 1846. 
Shell thin, horny, cylindrical, somewhat wider at the base; vertex truncated, narrowly, deeply 
impressed, minutely perforated, the lip inserted on right side of perforation; surface densely, evenly, 
spirally striated throughout, strife slightly wavy; aperture long, narrow and parallel sided above, wider 
below; columella very concave, folded above, the lip re flexed and appressed to the umbilical region. 
Length, 10; diameter, 6 mm. 
A single broken specimen was collected at Culebra Island, which seems to be this. 
Family HYDATINI DAL 
Genus HYDATINA Schumacher, 1817. ' 
Hydatina physis Linnfeus. 
Bulla physis Linnaeus, Syst. Nat., ed. X, p. 727, 1758. 
Hydatina physis Pilsbry, Man., xv, p. 387, pi. xlv, figs. 14-17, 1893. 
Porto Rico (Gundlach); West Indies; west Africa; central Pacific; Indian Ocean, etc. 
Genus MICROMELO Pilsbry, 1894. 
Micromelo undata Bruguiere. 
Bulla undata Brugniorc. Ene. Meth., I, p. 380, 1791. 
Micromelo undata Pilsbry, Man., XV, p. 392, pi. Lix, figs. 20-24, 1893. 
Porto Rico (Gundlach); West Indies; Honduras (Simpson). 
Family SCAPHANDRID4J. 
Genus ATYS Montfort, 1810. 
Shell solid, involute, oval, usually with spiral stria 1 at both ends; aperture projecting beyond the 
vertex and base; columella plicate or concave, generally somewhat reflexed over the small umbilicus. 
Type, A. cymbulus Montfort. 
