BIOLOGY, marine; — MAYER. 117 



Trematodes. — Beyond the preliminary examination made at the time of collecting, and 

 often of necessity hastily given, the collection has not been studied. 



From notes made during the preliminary examination it would appear that there are 

 about 33 species, many of which are new. Of these, all but nine could be referred to the 

 old genus Distomum. Three species of Gasteristomum were noted. Appendiculate dis- 

 tomes were seen in but two instances, one in the green moray and the other in the 

 Spanish sardine. Those from the moray were numerous and resembled the form which 

 I have been recording under the name D. monticellii; those from tlie sardine were few 

 and agree with D. appendiculatuni. 



Ivlany of the species are represented in the collection by but one or at most few 

 specimens, and it may be advisable to refrain from giving them names until more 

 material is secured. 



A distome, probably represented by more than one species, found in most of the lots 

 of gray snappers, grunts, and groupers, is unique in that the ova, as they lie in the 

 folds of the uterus, present a wreath-like appearance, and each ovum has a long, slender 

 filament, such as is common on the ova of monogenetic trematodes. 



Trematodes were found in large numbers in only two instances, a spade-fish, exam- 

 ined July i8, and a loggerhead turtle, examined July i. 



In general it may be said that the trematode fauna of Tortugas is rich in species. 



Ectozon. — Parasitic Isopods were found on the sting-ray, cabezote, yellow-finned 

 grouper, and a small shrimp common in the gulf-weed. 



Parasitic Copepods were found on only one fish, the Spanish sardine. 



One leech, colored vivid green and red-brown with blotches of white, was found on 

 the tongue of a nurse-shark. 



General Observations. — The groupers of the Tortugas like those of Bermuda, espe- 

 cially the older specimens, are characterized by having more or less abundant cysts on 

 the viscera and often in the walls of the stomach and intestine. These cysts are, as a 

 rule, dark brown, often nearly black. The color is due to the abundant pigment which 

 is deposited in the cyst. While these cysts are more often than otherwise due to ces- 

 todes, accumulations of pigment and degenerate connective tissue were also found 

 associated with other entozoa, viz, nematodes and acanthocephala in Bermuda, and 

 nematodes in Tortugas. 



It is perhaps worthy of remark that the great barracuda, which is a very voracious and 

 predatory fish, appears to harbor but few parasites, either as a final or intermediate host. 

 This conclusion is warranted also from the results of the examination of 5 barracuda in 

 Bermuda in 1903. The largest Tortugas specimen measured about 1.5 meters in length; 

 the Bermuda specimens were about one-half that length. 



It would be of interest to know whether the apparent immunity from parasites of the 

 barracuda and other fish is correlated in any way with the digestive ferments. 



Dr. Charles Zeleny carried out an extensive series of observations upon 

 regeneration, in order to determine the effect of successive injuries upon 

 the rate and character of regeneration in Crustacea. He also studied 

 regeneration in Cassiopea, and found that except in cases where all or 

 nearly all of the arms are removed there is an increase in the rate of 

 regeneration of each arm coordinate with an increase in the number of 

 removed arms. This confirms Zeleny's law that the animal with the 

 greater number of removed parts regenerates each and every part at a 

 more rapid rate than does the animal with the lesser number of removed 

 parts. Dr. Zeleny is now at work upon his observations, and hopes soon 

 to publish an account of his results. 



