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FISHERY BULLETIN OF THE FISH AND WILDLIFE SERVICE 



to slide over the slimy bottom, or burrowing forms 

 as the Molpadonia and deep water Apoda, and 

 the ledges along the north coast of Cuba and 

 Yucatan with a depth of 200 to 500 fathoms and 

 inhabited by offshots of the shallow water fauna, 

 mostly Aspidoehirota and Synallactidae. 



In 1930 an attempt was made to trace the origin 

 of the West Indian holothurian fauna on the basis 

 of what was then known. The following 20 years 

 have added so much to our knowledge about the 

 distribution of the holothurians of the American 

 waters, the result of the Hancock expeditions along 

 the west coast of Mexico and Central America 

 and the Harvard-Havana expeditions around 

 Cuba, that many of the statements set down then 

 have had to be modified or entirely reversed. 



The deep water forms, the Elasipodae, Synal- 

 lactidae, and a few Holothuriidae, represent a 

 selection of the Atlantic fauna. Most of them 

 are typical mud dwellers which occur widespread 

 in the Atlantic Ocean in deep water, but the 

 Atlantis expeditions have added a number of forms 

 hitherto known only from the eastern part of the 

 Atlantic occurring close to the shore and from 

 moderate depth, 200 to 500 fathoms or so. Some 

 of these have been taken inside of the Gulf area 

 along the northern coast of Cuba, and they may 

 very likely prove to be a characteristic element 

 in the southern part of the Gulf. 



The order Molpadonia have a few representa- 

 tives from moderate to great depth. With a single 

 exception, the widespread Molpadia musculus, 

 they all appear to be endemic, though one may 

 expect that most of them have a parallel form in 

 the Pacific. The single representative of the order 

 Apoda is known from deeper water off the Atlantic 

 Coast of North America, and in the end it may 

 be united with a closely related species reported 

 from the eastern Pacific. 



Among the typical shallow water forms, which 

 mostly are taken at low tide or a few fatlioms 

 depth though some go down to almost 200 fathoms, 

 we find that the Aspidoehirota have no affinities 

 with the eastern Atlantic {Holothuria impatiens 

 is a circumtropical form, while H. mexicana and 

 Stichopits hadionotus, though reported from the 

 eastern Atlantic, appear not to belong there; 

 it may be either wrong labeling, or they may have 

 become accidentally introduced without being 

 permanently established). The Aspidochirotes 

 have their closest affinities with tJie Indo-Pacific 



fauna; a few somewhat similar species occur also 

 in the Panamic region, but we are not able to 

 speak of truly parallel forms. On the other 

 hand, the dendrochu-otes which 20 years ago were 

 considered endemic have now, thanks to the 

 Hancock expeditions, been found to have in 

 most cases a parallel form in the Panamic region 

 but no close affinities with the remaining part of 

 the Pacific Ocean nor with the eastern Atlantic. 

 An exception is Thyone inennis, a Mediterranean 

 form of which immature specimens have been 

 taken, off and on, around Florida and at Tobago 

 but not in the Gulf itself. Some dendrochirotes 

 appear to be absent in the West Indies as a whole 

 but occur in the northern part of the Gulf and 

 along the Atlantic seaboard (Thyone hriareus and 

 Thyonella gemmata). There is only one true 

 shallow water form of the order Molpadonia, 

 though others have been taken in abnormally 

 shallow water; this species, Paracaudina oh- 

 esacauda, is, as far as known, restricted to the 

 Gulf, and the genus is not otherwise known from 

 the Atlantic Ocean. A number of closely related 

 species in shallow water are found in the Pacific, 

 ranging from Chile northward to Alaska, from 

 Japan, China, Australia to New Zealand. When 

 it comes to the order Apoda, our knowledge is 

 still most unsatisfactory. The few, purely tropical 

 species Icnown from the West Indies will un- 

 doubtedly be found widespread in the southern 

 part of the Gulf, on the reefs, while offshots from 

 the forms found along the Atlantic seaboard 

 may be expected in muddy and sandy localities 

 between Florida and Texas and possibly farther 

 south along the east coast of Mexico. Nothing 

 can be said about the affinities with the Panamic 

 fauna of Apoda as it is still almost unknown. 

 Very likely it is almost nonexisting as much of the 

 shoreline of the west coast of Mexico and Central 

 America is ill-suited for these forms. With the 

 fauna of Apoda from the eastern Atlantic and the 

 Mediterranean there seem to be no close affinities. 



TECHNIQUE 



Holothurians may be anesthetized with chlore- 

 tone or Epsom salt, or even stale sea water. By 

 slowly adding alcohol one is often able to have 

 them preserved in reasonably well-expanded condi- 

 tion. Large species may later have an incision 

 made in the skin so that alcohol can penetrate 



