ANOMURAN COLLECTIONS MADE IN PORTO RICO. 
133 
Genus HYPOCONCHA. 
Hypoconcha sabulosa (Ilerbst). 
Cancer sabulosa Herbst, n, p. 57, pi. 48, figs. 2 and 3, 1799. 
Hypoconcha sabulosa Gufirin, Rev. et Mag. Zool. (2), vi, p. 333, pi. 5, 1854. Stimpson, Proc. Arad. Nat. Sci. Phila. 1858, p. 226; 
also Ann. Lye. Nat. Hist. N. Y., vn, p. 72, March, 1859. 
This and the following species are very much alike and have similar habits. The front and lateral 
margins are expanded, covering the eyes and all parts of the head except the flagella of the antennae; 
the middle surface is very thin and membranous. There is but little hair on the surface of the 
specimens examined; the margin is heavily fringed with bristles and armed with a number of white 
spines. In outline this species is a little flattened in front and there is a large notch on the median 
line; tb -re are no notches over the antennae; the sides are a little flattened, but are not concave as in 
1 lerbst’s figure. The fourth and fifth pairs of feet are prehensile without being subchelate as in Dromia. 
The shape of this crab has, like that of the hermit crabs, been modified to suit its dwelling or protective 
covering, for it holds over its carapace the valve of some lamellibranch, holding on by some of its 
posterior feet and perhaps, as Dr. Stimpson suggested, by the angular abdomen inserted under the hinge. 
Herbst’s specimens were from Africa, while the other writers have all had them from the West 
Indian region, and it is not unlikely that the African species may prove to be the true sabulosa and 
that the species in hand may differ more from that than from II. arcuata. 
Length of an individual, 11.5 mm. 
Hypoconcha arcuata Stimpson. 
Hypoconcha arcuata Stimpson, Ann. Lye. Nat. Hist. N. Y., vn, p. 72, March, 1859. 
In comparison with II. sabulosa this species is more evenly rounded in front and on the sides; 
there is a deep fissure on the middle of the front rather than a notch; there are slight notches above 
the antennae; the white spines that arm the border are smaller and more numerous. 
Length, 115 mm.; width, 11.8 mm. 
Genus PETROLISTHES. 
Petrolisthes sexspinosus (Gibbes). 
Porcdlana scxspinosa Gibbes, Proc. Amer. Assoc, for Adv. of Science, in, 1850, p. 190. 
Petrolisthes sexspinosus Stimpson, Proc. Acad. Nat. Sci. Phila. 1858, p. 227. Kingsley, Proc. Acad. Nat. Sci. Phila. 1879, p. 405. 
The front is produced, triangular. The carapace is crossed by numerous rugose and ciliated lines; 
similar lines cross the chelipeds diagonally. Four large triangular, spine-pointed teeth arm the inner 
margin of the carpus. 
Many specimens of this species were taken at Ensenada Honda, Culebra; some agree well with 
specimens from Florida, others have a row of four or five spines on the movable finger of the hand. 
At first the spiny-fingered variety seemed to be specifically distinct, as the color was different; after- 
wards the spines were found on specimens of all varieties of color. The larger and more numerous 
specimens are purple and white, the ridges taking the color while the intermediate spaces are occupied 
by the cilia, which under a lens become white plumes. In another variety the purple is changed to 
red, and in these there is likely to be a double cross on the carapace, caused by a line or light streak 
running from the rostrum to the posterior margin, and two transverse lines, one between the eyes and 
one near the center; specimens with this color are more likely to have the spiny fingers than the 
larger purple and white ones. , 
Common throughout the West Indies and southern coast of the United States; Porto Rico, at San 
Juan, Boqueron, Ensenada Honda (Culebra), Mayaguez Harbor, Caballo Blanco Reef, and other 
localities; stations 6075 and 6065. Length, 7.5 run.; width, 6.5 mm. 
Petrolisthes armatus (Gibbes). 
Porcellaha armata Gibbes, Proc. Amer. Assoe. for Advancement of Science, in, 1850, p. 190. 
Porccllana gundlachii Guerin, in La Sagra’s Hist, of Cuba, vm (Atlas), 1855, Artieulata, pi. ir, fig. 6. 
Petrolisthes armatus Stimpson, Proc. Acad. Nat. Sci. Phila. 1858, p. 227. Kingsley, Proc. Acad. N it. Sci. Phila. 1879, p. 406. 
The front is obtuse and but little produced. The carapace is crossed by numerous broken lines of 
minute ridges. The chelipeds are long; the carpus has three equidistant teeth on inner margin and 
four or five curved teeth on outer margin. The hand has a line of spinules on the lower margin; 
in some specimens the spinules are wanting; surface of hand roughened by short lines of granules. 
San Juan and Boqueron Bay. Length, 9.5 mm.; width, 9 mm. 
