about one-third length of last article; acicles 

 slender, curved sinuously outward, reaching to 

 tip of cornea; flagella exceeding tip of major 

 cheliped. 



Right cheliped much larger and longer than 

 left, subcylindrical, devoid of hairs except for a 

 few short setae along inner edges of fingers; 

 width of hand less than one-half total length, 

 palm lightly crested and minutely dentate along 

 outer margin, upper surface minutely granulate 

 and with two incomplete rows of larger granules 

 near proximal end; fingers short, hooked at tips; 

 carpus as long as propodus to middle of finger, 

 with two rows of subspinous tubercles and 

 scattered smaller ones. Left cheliped smaller, 

 hairier, similarly formed but relatively broader; 

 fingers with cutting edges distally, gaping at base. 

 First and second walking legs with dactyls longer 

 than propodi, extending about as far as chelipeds. 

 Third and fourth pairs of legs reduced in size, 

 fourth turned upward on back. 



Measurements. — Length of carapace: male, 10 

 mm.; ovigerous female, 11 mm. 



Color. — Color varies with locality; specimens 

 of west Florida are lighter than those of east 

 coast ; upper surface of chelipeds and all walking 

 legs iridescent ; posterior carapace light green ; 

 hand white with median diffused pigment stripe, 

 carpus with dorsal stripe and one on each side; 

 walking legs with dactyl unstriped, propodus 

 with lateral stripe, merus with single lateral 

 muddy brown stripe and transverse stripe from 

 lower anterior margin to broad pigmented area on 

 upper surface; antennae with dark bands alter- 

 nating with shorter white bands. Young may have 

 transverse band on each article of walking legs 

 rather than stripe; lateral stripes of major che- 

 liped with V-shaped appearance in dorsal view 

 (Provenzano, 1959, from west Florida specimen). 



Habitat. — Common on harbor beaches, in har- 

 bor channels, and in shallow littoral on a variety 

 of bottoms; to 27.5 fathoms (possibly beyond). 



Type locality. — "Inhabits Bay Shores" [east 

 coast of United States] . 



Known range. — Minas Basin, Nova Scotia 

 (Rathbun, 1929) to northern Florida; Sanibel Is- 

 land, Fla., to coast of Texas (Provenzano, 1959; 

 Whitten, Rosene, and Hedgpeth, 1950). 



Remarks. — Pagurus longicarpus is one of the 

 commonest decapod crustaceans in shallow water 



along the coast of the Eastern United States. Like 

 other similarly available crustaceans, it has been 

 the subject of a number of ecological and physio- 

 logical studies, and these have been accomplished 

 mostly around Woods Hole, Mass. Provenzano 

 (1959) suggested that the Atlantic coast and Gulf 

 of Mexico forms, with a hiatus between their 

 ranges, may be subspecifically distinct. 



The general habitat of P. longicarpus, sum- 

 marized above, has been commented upon by other 

 authors (Pearse, Humm, and Wharton, 1942; 

 Allee, 1923). Allee concluded that the ubiquity of 

 this hermit crab prevents it from being of aid in 

 distinguishing shallow-water communities. Dia- 

 toms, detritus, and algae make up the food of this 

 species (Sanders, Goudsmit, Mills, and Hampson, 

 1962). 



The breeding season of this common form ex- 

 tends from early May to mid-September (Bumpus 

 in Sumner, Osburn, and Cole, 1913b) in Massachu- 

 setts, and ovigerous females have been taken in 

 January, March, and September in Florida 

 (Wass, 1955, in part). Thompson (1901, 1903) 

 described four zoeae, a glaucothoe, and a first 

 postlarval stage, as well as various adolescent 

 stages. He compared larval development of P. 

 longicarpus with that of P. annulipes and gave re- 

 marks on the derivation and geological age of 

 pagurids. 



Autotomy and regeneration in this species re- 

 ceived attention from Morgan (1900, 1901) and 

 Haseman (1907), though investigations on this 

 subject with other species now supersede the early 

 studies. The first three pairs of legs have a frac- 

 ture joint near their bases; hence, can be autot- 

 omized, but the last two pairs lack these and 

 cannot be autotomized. Injuries distal to the frac- 

 ture plane result in autotomy and regeneration; 

 those proximal to the plane do not result in autot- 

 omy. Injured abdominal appendages are readily 

 regenerated. Haseman carried this work farther, 

 showing that when the chelipeds were removed at 

 their breaking joints they differentiated from the 

 tip proximally, but the first two pairs of clawed 

 (walking?) legs differentiated from the base to- 

 ward the tip. Direction of differentiation in the 

 cheliped can be reversed by injuring the develop- 

 ing bud. 



In another vein, conditioned and natural behav- 

 ior of P. longicarpus has been the subject of a few 



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