328 



FISHERY BULLETIN OF THE FISH AND WILDLIFE SERVICE 



NOTES ON THE RANGE OF SPECIES 

 COLLECTED IN THE GULF OF MEXICO 



S. hispida was collected regularly from the 

 diluted inshore waters along the Gulf coast of 

 Florida. In the Fort Myers and Sarasota region 

 it was not usually taken more than 10 miles 

 offshore. This species has also been collected 

 from the Cedar Keys region, off Cape Sable, the 

 Florida Keys, and 12 miles north of Key West. 



Because Conant (1895) failed fully to describe 

 this species which he obtained from Beaufort 

 Harbor, North Carolina, a certain amount of 

 confusion has resulted in later attempts at iden- 

 tification. A comparison of my specimens with 

 the material deposited by Conant in the United 

 States National Museum leaves little doubt about 

 their identity. 



S. helenae was a very common species along the 

 Gulf coast of Florida. It was not usually found 

 in the diluted inshore belt of water as was S. 

 hispida but was most abundant 5 miles or more 

 offshore where water of approximately normal 

 salinity was encountered. 



This species was collected about 40 miles west 

 of Sarasota and probably is to be found much 

 farther offshore in the Gulf. A sample collected 

 by the Albatross on March 3, 1885, about 50 

 miles southeast of the mouth of the Mississippi 

 River contained specimens of S. helenae. Ritter- 

 Zahony (1910) obtained it from the Dry Tortugas 

 area and suggests that it is a definitely neritic 

 species. 



S. tenuis is also a common form along the west 

 coast of Florida. This small chaetognath, ma- 

 turing occasionally at 5 millimeters, was taken 

 in water whose salinity varied from 24 to 35 parts 

 per thousand. It was described by Conant in 

 1896 from specimens obtained in Kingston Harbor, 

 Jamaica. This species was not recognized by 

 Ritter-Zahony (1910) who, not having access to 

 Conant's material in the United States National 

 Museum, failed to consider it a valid species. 

 No references have been found coacerning the 

 distribution of S. tenuis in the Gulf of Mexico. 



S. enjlata, by way of contrast, is a true cos- 

 mopolitan form and is taken in abundance in the 

 warm waters of all oceans both over the continental 

 shelf and in the open ocean as well. Moreover, 

 it may be collected from the surface to a depth of 



several hundred meters. Common along the west 

 coast of Florida, in the Florida Current, and in 

 the offshore samples taken by the Atlantis in the 

 Gulf, this species is almost certainly very abundant 

 and widely distributed in the Gulf of Mexico. 



Little is known about the distribution of S. 

 bipunctata, S. serratodentata, S. hexaptera, S. lyra, 

 and S. macrocephala in the Gulf of Mexico. Rit- 

 ter-Zahony (1910) records the first two species 

 from the Dry Tortugas area but apparently did 

 not find the latter three in the collections he 

 examined which, incidentally, were all taken near 

 the surface. These species are all found in the 

 tropic and temperate regions of the Atlantic, 

 Pacific, and Indian Oceans. S. lyra and S. 

 macrocephala are not typically epiplanktonic forms 

 but are found most abundantly 100 meters or 

 more beneath the surface. As indicated earlier, 

 none of the above were taken in the waters of the 

 west coast of Florida. They are essentially open- 

 water chaetognaths. 



Krohnitta pacifica was collected occasionally 

 from the west coast of Florida. It was never 

 very abundant. This species has also been re- 

 corded from Australian and Japanese waters. 

 Past errors in its taxonomic status cast some 

 doubt on the extent of its distribution. 



Krohnitta subtilis was found in each of the 

 Atlantis samples from the Gulf and was never 

 taken close to shore. It is also common to the 

 waters of Australia and Japan. 



Eukrohnia hamata was present in one of the 

 Atlantis samples. It was never found along the 

 west coast of Florida. This species has been taken 

 in the Atlantic, Indian, and Pacific Oceans. 



In order that we may extend our very meager 

 knowledge of the occurrence of the chaetognaths 

 in the Gulf of Mexico added samples are needed 

 from the northern and western portions and espe- 

 cially from the surface and deep waters in the 

 central portion of the Gulf. Studies of such sam- 

 ples will not only add to our information of the 

 distribution of the Chaetognatha but will increase 

 our knowledge of the effects of water movement 

 on the Gulf plankton generally. 



SUMMARY 



Fourteen valid species of chaetognaths have 

 been collected from the Gulf of Mexico. Five of 



