GULF OF MEXICO 



245 



localities, and little attempt has been made to 

 determine the extent of distribution. The excep- 

 tions are Nematopsis ostrearum and Dermocy- 

 stidium marinum (see footnote, p. 244), both para- 

 sites of the oyster Crassostrea nrginica. Although 

 much information accumulated by numerous in- 

 vestigators relative to these two parasites re- 

 mains unpublished, a comprehensive report by 

 Landau and Galtsoff (1951) on the Distribution 

 of Nematopsis has recently appeared. Since little 

 can be said positively about the distribution of 

 parasitic Protozoa in general, and those in the 

 Gulf of Mexico in particular, this is a subject full 

 of promise for future study. It would be of 

 particular interest, from the economic point of 

 view, to add to our meager information more data 

 on the distribution of the protozoan parasites of 

 such commercially important seafood animals as 

 the shrimp, crabs, and oysters. 



Subphylum 1 PLASMODROMA 

 Doflein 1901 



Class 1 Mastigophora Diesing 1865 



Subclass 1 Phytomastigina Doflein 

 1916 



The Phytomastigina include those flagellates 

 in which the plant characteristics are either pre- 

 dominant or clearly marked. Of the six orders, 

 two (Phytomonadina and Euglenoidina) are pre- 

 dominantly freshwater forms commonly consid- 

 ered to be Algae as well as Protozoa, one (Chloro- 

 monadina) consists of rare and little known 

 flagellates, another (Dinoflagellata) is so promi- 

 nently represented in the Gulf that it is given 

 separate treatment, and the other two (Cliryso- 

 monadina and Cryptomonadina) are commonly 

 represented in salt water, but the writer knows of 

 practically no reports on them from the Gulf. 

 The Phytomastigina are, therefore, given very 

 little consideration here. 



Order 1 CHRYSOMONADINA Stein 1878 



Although the Silicoflagellidae are exclusively 

 marine plankton, and the Coccolithidae are 

 mostly marine, the writer is not familiar with 

 reports of members of this order from the Gulf of 

 Mexico. 



Order 2 CRYPTOMONADINA Stein 1878 



"The Cryptomonadina occur in fresh or sea 

 water, living also often as symbionts in marine 

 organisms." (Kudo, 1946, p. 213). 



Suborder 1 Eucryptomonadina Pascher 1913 



Family CRYPTOMONADIDAE Stein 



1. Chilomonas (?). 



This organism was observed by Pearse (1932) in a 

 bracki.sh water pool (Pool 5) at Garden Key, Tortugas. 



Order 3 PHYTOMONADINA Blochmann 

 1895 



These are mostly fresh water Algae. 



Order 4 EUGLENOIDINA Biitschli 1884 



Members of this order are likewise mostly fresh 

 water Algae. 



Order 5 CHLOROMONADINA Klebs 1892 



"The chloromonads are of rare occurrence and 

 consequently not well known." (Kudo, 1946, p. 

 243.) 



Order 6 DINOFLAGELLATA Butschli 1885 



The dinoflagellates, which include many well- 

 known planktonic forms in the Gulf, are treated 

 separately (pp. 223-226). 



Subclass 2 Zoomastigina Doflein 1916 



The majority of this subclass are either parasitic 

 in land dwelling or fresh water animals or free 

 living in fresh water. 



Order 1 RHIZOMASTIGINA Butschli 1883 



Although some members of this group occur in 

 salt water, the writer is not aware of reports of 

 any of them from the Gulf of Mexico. 



Order 2 PROTOMONADINA Blochmann 1895 



Organisms belonging definitely to this order 

 seem not to have been reported from the Gulf. 

 However, certain trypanosomelike organisms 

 (now generally regarded as spirochaetes) very 

 commonly occur in the intestinal tracts, especially 

 in the crystalline styles, of various lamellibranch 

 mollusks in many parts of the world. It is com- 

 mon knowledge among oyster biologists that they 

 occur in oysters of the Gulf, although no one seems 

 to have recorded the fact. Those organisms are 

 mentioned here for lack of a better place to con- 

 sider them. Dimitroff (1926) made an intensive 

 study of the spirochaetes of Baltimore market 

 oysters. He gave a complete review of the litera- 

 ture and listed 11 species or varieties which he 

 found. He assigned 4 of the types to Saprospira 

 Gross, 1910, and 7 to Cristispira Gross, 1910. 

 Possibly the spirochaetes of Gulf coast oysters, 



