cm. The mouth opening was slightly over 1 m. in 

 width. This nigged dredge was used on rocky 

 ledges as well as on level bottoms. Use of the 

 smaller, lighter, and less rugged Cape Town 

 dredge was limited mainly to level bottoms. Char- 

 tered shrimp trawlers and Duke Marine Labora- 

 tory's RV Eastward were used in the dredging. 



For such forms as Astrofecten and Luidia that 

 glide over the sandy substrate and feed by inges- 

 tion of numerous small surface organisms, com- 

 mercial trawls proved veiy satisfactory. Diving on 

 reefs in relatively shallow water and using 

 SCITBA (Self Contained Underwater Breathing 

 Apparatus) produced some species not taken by 

 other means, but this excellent collecting method 

 was not used beyond a depth of 30 m. 



Bottom photographs have sometimes helped 

 demonstrate relative abundance, but only rarely 

 can these be used alone for positive identification of 

 species. Also, many sea-stars cannot be satisfacto- 

 rily photogi-aphed tecause they bury themselves 

 beneath the substrate and leave only an imprint to 

 indicate their presence. 



Probably some species which appear to be scare© 

 would prove to be. more abundant if more suitable 

 methods for tlieir collection were used, especially 

 on reefs, ledges, and rock outcroppings too deep 

 for nonnal SCUBA diving. 



Not all parts of the shelf have been sampled with 

 equal intensity, and our list of asteroids is prob- 

 abl}^ incomplete. The most frequent cx)llections 

 have l>een made between the latitude of Oregon In- 

 let, well north of Cape Hatteras, and New River 

 Inlet, well south of Cape Lookout. Material is 

 more scanty from the area off Cape Fear and Fly- 

 ing Pan Shoals. Nevertlieless, we believe that the 

 data pi-esented justify the assumption that most of 

 the species to be found in North Carolina are in- 

 cluded, since the areas tliat have Iwen extensively 

 sampled cover the principal marine biotic prov- 

 inces. The most serious potential source of error 

 lies not in the range of latitude sampled but in the 

 lack of adequate collections from reefs and hard 

 bottoms. 



PRESERVATION TECHNIQUES 



Starfishes should preferably be relaxed before 

 preservation, but this is not always possible on 

 shipboard. Some species normally remain flat, but 

 in others the anns tend to curl. They can be relaxed 

 and preserved in sea water in a flat enamel pan 



large enough for the specimens to spread out with- 

 out touching one another. The sea-stars flatten if 

 magnesium sulphate (Epsom salt) is sprinkled on 

 the water or if fresh water is added, a little at a 

 time, until the sea water is replaced. Regardless of 

 method, after relaxation is completed the water 

 should be replaced by 70 percent alcohol or by 6 

 percent neutralized Fonnalin.* Echinoderms 

 should never be kept jDermanently in Fonnalin, 

 however, as it destroys their calcite plates. Un- 

 fortimaitely, and perhaps unavoidably, alcohol re- 

 moves much of the color. Usually it is more satis- 

 factory to dry specimens after they have been 

 presen-ed; this solves many storage problems. If 

 later there is need to examine soft parts (e.g., to 

 detennine whetlier or not tlie podia have suckers) , 

 the whole specimen, or better still, a single arm can 

 be soaked for a few hours in ordinary detergent. 

 To examine underlying plates or other hard parts, 

 soft tissue can be removed by dipping the appro- 

 priate part of the animal in household bleach. 

 Bleach must be used carefully ; excessive amounts 

 can easily remove all connective tissue holding the 

 plates together. The action of bleach can be quickly 

 ended by rinsing the specimen in rumiing water. 

 It is best to treat only one arm of a specimen, as 

 it may te desirable later to check certain anatomi- 

 cal features of the soft tissues. 



To examine pedicellariae, one or two can be re- 

 moved mider magnification with fine foi-ceps and 

 placed on a glass slide with a drop of dilute bleach. 

 Bleach will not always be necessaiy, as the valves 

 of the pedicellariae are sometimes clearly visible 

 without further treatment. 



BIOGEOGRAPHICAL AREAS 



Analysis of the distribution of any major group 

 of bentliic species on any segment of the North 

 Atlantic Continental Shelf holds more than local 

 interest. This is especially tiaie of the North 

 Carolina section of the shelf, which in any discus- 

 sion of north-south distribution of species occupies 

 a position of marked biogeographic importance. 

 Located about midway on the U.S. Atlantic coa.st 

 between temperate New England and subtropical 

 Florida, the North Carolina shelf has several ma- 

 rine climates and associated temperature barriers 

 within relatively few kilometers. Several capes. 



* Trade names referred to in this publication do not imply 

 endorsement of commercial products. 



128 



U.S. PISH AND WILDLIFE SERVICE 



