"SLIPPER LIMPET" OR "BOAT SHELL." 405 



constriction are bordered by rows of vibratile cilise, which create 

 brisk currents, and serve to move the embryo. When the Crepi- 

 dula is at rest the front edge of the shell is a little raised, and 

 the tentacles thrust a little forth. They move slowly from time 

 to time." 



In our waters, as yet, we have not met with the " Slipper 

 Limpet" on shells occupied by the Hermit Crab, but certainly 

 we shall keep a sharp look-out for them. The remainder of 

 Lyman's description of the soft parts corresponds or tallies with 

 our examination and dissection of quite a number of the British- 

 bred specimens. See drawings of same in Plate VI., figs. 11, 12, 

 13, 14, and 15. 



In his Eeport to the Commissioner of Fish and Fisheries,* 

 Prof. A. E. Verrill, in describing the fauna of the gravelly and 

 shelly bottoms of the bays and sounds off Massachusetts, re- 

 marks of Crepidida fornicata that it: — "Was one of the most 

 abundant species, often occurring adhering to each other in 

 great clusters, the lowest ones in the group adhering in turn to 

 dead bivalve shells, pebbles, shells of living Fulgur and Sycoty- 

 pus, and still more frequently to these shells when dead and 

 occupied by the larger Hermit-Crabs {Eupagurus pollicarus). 

 The dead shells of this Crepidida were often found in great 

 accumulations, covering considerable areas of bottom, and with 

 little admixture, either with other shells or with sand and 

 gravel." 



The same writer {I.e. p. 475), in enumerating the animals 

 inhabiting the Oyster-beds in brackish water, says: — "Among 

 the most common shells that are found attached to Oysters are 

 Crepidula fornicata and C. unguiformis. They both occur 

 together on the upper as well as the under valves, and in all 

 cases retain their ordinary characters." 



See the figures in accompanying Plate VII. of how C. forni- 

 cata grasps and perches on Oysters, Mussels, &c., in the estuarine 

 and creek waters of Kent and Essex, all showing its habits and 

 attachments have not altered in new surroundings. 



During the Great International Fisheries Exhibition, held 



* " Eeport upon the Invertebrate Animals of Vineyard Sound and the 

 adjacent Waters, with an Account of the Physical Characters of the Eegion," 

 in Eep. U. S. Commiss. Fish and Fisheries, vol. i. p. 417 (1873). 



