^P. interruptus.^ This is the California spiny lobster, rock-lobster, or salt-water crawfish. It differs from the common lobster /Homarus/ of the Atlantic coast in having no large claws, the first pair of feet being simple like the rest, also in having antennæ which are enormously long and very large at the base. The carapace is beset with spines, and the lateral margins of the abdominal segments end in spines. This species lives among the rocks on the southern California coast. [Illustration: /Panulirus interruptus/, the spiny or rock-lobster.] ^P. argus^ or ^americanus^ resembles /P. interruptus/, and is found on the coast of Florida. GENUS ^Scyllarus^ /Scyllarus/ has a broad, almost square carapace, which is uneven and coarsely granulated; the anterior corners are sharp, the posterior ones rounded. The antennæ are curiously modified into broad, flat, double plates reaching quite across the straight anterior end of the carapace. The under scales of these modified antennæ are rounded and leaf-like, the upper ones are pointed. The margins of the abdominal plates on the ventral side are toothed, and on the upper side the first three sections have [pg264] knobs, the third one being the most prominent, and forming the posterior extremity when the abdomen is folded in. The walking-feet are all simple and end in points; the first pair are the longest, and the following ones gradually diminish in size. The ventral surface is rough and spiny. The abdomen is of about the same length as the carapace. These animals are found off the Florida coast and are caught in the fish-traps. They are uncommon. The very peculiar development of the antennæ makes them worthy of examination when opportunity offers. ANOMALOUS FORMS: ANOMURA The anomalous forms which are intermediate between the suborders /Macrura/ and /Brachyura/ were, until recently, placed in a suborder, /Anomura/. The members of this group differ from one another, and some of them resemble in external features members of the other divisions of the suborders, but there is a difference in anatomical structure which separates them in the classification. FAMILY ~DROMIDÆ~ GENUS ^Hippoconcha^ ^H. arcuata.^ This curious little crab, found on the Florida coast, carries the half of a bivalve shell over its back. Its fifth pair of thoracic legs are bent over the back, and these, together with the fourth pair of legs and the spiny front edge of the carapace, enable the crab to hold the shell in position. This crab was formerly classed with the hermits, all of which were originally called /Bernhardus/, after the monk of that name. FAMILY ~PAGURIDÆ~ THE HERMIT-CRABS