ANOMALOUS FORMS 269 



for pushing and digging. Crabs of this species are gregarious and 

 may be seen in great numbers, though but few will be captured together 

 by digging, as they rapidly disappear beneath the sand. Sometimes they 

 are found swimming about in the tide-pools. They seem to live upon 

 the organic particles contained in the sand, which they swallow, the 

 mouth not being adapted for mastication. This species ranges from 

 Cape Cod to Florida. (Plate LXI.) 



H. analoga. Similar to H. talpoida, but broader and flatter. It is 

 bluish above, yellowish-white below, and the fringing hairs are black. 

 Found on the California coast. 



GENUS Albuncea 



A. gibbesii. This animal is found with Hippa, and, like it, burrows 

 rapidly in the sand. Its general outline is square. The surface of the 

 carapace is marked off with denticulated lines, which make the back ap- 

 pear as if composed of plates. The front edge of the carapace has a row 

 of teeth and a prominent spine at the anterior angles. The abdomen is 

 doubled under itself (not fitting into a groove of the thorax, as in ordi- 

 nary crabs), this animal being intermediate between the long- and the 

 short -tailed forms. The eyes are on triangular, plate-like stalks. The 

 antennules are very long and are fringed with hair. The chelipeds have 

 claw-like joints, which close across the straight, broad end of the hand. 

 The first two pairs of walking-feet have curious sickle-like terminal 

 joints. The animal is about one and a quarter inches long. Albuncea 

 does not extend as far north as Hippa, its range being from Georgia 

 southward. (Plate LXI.) 



FAMILY PORCELLANIDJE 



The crabs of this family are little more than one quarter to 

 one half of an inch across the back. The chelipeds are broad 

 and flattened. The first three pairs of walking-legs are well de- 

 veloped, and the fifth pair are very small and are doubled over 

 the base of the carapace. The sixth segment of the abdomen 

 has a pair of biramous appendages, which, with the telson, form 

 a swimming-fan. 



GENUS Porcellana 



P. sayana. Carapace little longer than broad ; breadth about one 

 quarter of an inch ; smooth ; has three acute denticulations between the 

 eyes, the middle one the largest and depressed in the center ; two dentic- 

 ulations on each anterior side ; chelae fringed with hair on the edges ; 

 walking-legs somewhat hairy ; fifth pair of legs folded over base of cara- 

 pace ; color reddish, with white spots. This species was once called occu- 

 lata, because of the eye-like spots over its entire surface. The posterior 

 part and abdomen have longitudinal bands of color. The claws are 

 marked like the shell. Found from South Carolina southward, often in 

 the shells inhabited by hermit-crabs. (Plate LXI.) 



