250 



FISHERY BULLETIN OF THE FISH AND WILDLIFE SERVICE 



cation, 1950) in a common tube-dwelling annelid, 

 Spirochaetoptems sp., and in the intestines of 

 Polydora wehsUri (Hartman), a common poly- 

 chaete infesting the shells of oysters. 



Order 2 COCCIDIA Leuckart 1879 



The writer knows of no members of tliis order 

 which have been reported from the Gulf of Mexico. 

 It is possible, however, that they may be present 

 in some of the numerous species of vertebrates 

 there. 



Order 3 HAEMOSPORIDIA Danilewsky 1886 



Excepting Plasmodium, which occurs in the 

 vicinity of the Gulf but which does not seem to fall 

 within the scope of this paper, the author knows 

 of no Haemosporidia reported from the area. 



Subclass 2 Acnidosporidia Cepede 1911 



Order 1 SARCOSPORIDIA Balbiani 1882 



The Sarcosporidia, being chiefly parasitic m 

 the muscle tissues of mammals, seem not to have 

 been reported from the Gulf. 



Order 2 HAPLOSPORIDIA Gaullery and 

 Mesnil 1899 



It is customary to place in this order any 

 organism which seems to have sporozoan affinities 

 but does not belong to any other order. Conse- 

 quently, Haplosporidia includes a heterogeneous 

 assemblage of unrelated organisms. Some of 

 them should probably be assigned to new orders, 

 and some others may be more closely related to 

 fungi than to Sporozoa. The one common char- 

 acteristic is the lack of polar filaments in the 

 spores. Although there are many types of spores 

 represented in this order, some of them have a 

 striking superficial resemblance to those of Micro- 

 sporidia. Only one species (previously unre- 

 corded) which can unquestionably be properly 

 assigned to Haplosporidia seems to be known 

 from the Gidf. Two others are provisionally 

 included here pending further information. 

 1. Haplosporidium sp. 



Observed by Sprague in January 1948 in the vicinity of 

 Grand Isle, Louisiana, in only one of many specimens of 

 the common mud crab, Panopeus herbstii Milne Edwards 

 (kindly identified by F. A. Chace, Jr., of the United 

 States National Museum). 



The intestine, covered on the outside with the spores, 

 has a conspicuous dark brown appearance. 



2. "A haplosporidian (microsporidian?)". 

 In Gymnophallas .sp. (metacercariae). 



A trematode parasite of the clam Donax sp. from Port 

 Aransas, Te.xas, was reported by Hopkins (1950) in a 

 personal communication to the author. 



3. DermocijMidium marinum Mackin, Owen and Collier, 



1950. 



Found to be widely distributed in Crassostrea virginica 

 (Gmelin), the commercial oyster, along the Gulf coast. 

 It infects any of the host tissues, especially the intestinal 

 epithelium, adductor muscle, gills, mantle, and heart. 

 Although there is great uncertainty about the taxonomic 

 position of the genus Dermocystidiuni, it is usually placed 

 in the Haplosporidia (see footnote, p. 244). According to 

 Mackin et al. (1950), the parasite has been found asso- 

 ciated "with dead or dying oysters under certain environ- 

 mental conditions, the limits of which can be reasonably 

 well-defined. The chief controlling factors appear to be 

 temperature and salinity, low temperature and low salinity 

 evidently retarding the development of the infestation" 

 (p. 329). 



Subclass 2 Cnidosporidia Doflein 1901 



Order 1 MYXOSPORIDIA Butschli 1881 



The writer knows of no Myxosporidia which 

 have been reported from the Gulf of Mexico, 

 although there is no reason to doubt that they 

 occur there. As Kudo (1946) has pointed out, 

 these organisms are exclusively parasites of lower 

 vertebrates, especially fish. Davis (1917) and 

 others have described numerous species found in 

 various fish of the Atlantic coast. The fact that 

 many of the same species of fish occur also in the 

 Gulf of Mexico is reason to suspect that many 

 of the known Myxosporidia also occur there. 

 Doubtless, a search for these neglected forms would 

 be rewarded by the discovery of many new and 

 known species. 



Order 2 ACTINOMYXIDIA Stolg 1899 



This order contains but few known species, 

 all occurring in fresh or salt-water annelids, and 

 none apparently having been reported from the 

 Gulf. In view of the great variety and numbers 

 of annelids in the Gulf, however, it is quite possible 

 that species of Actinomyxidia occur there. 



Order 3 MICROSPORIDIA Balbiani 1883 



The Microsporidia, being typically parasites 

 of artliropods and fish (although they are repre- 

 sented in several animal phyla), are probably 

 common parasites in animals of the Gulf. The 



