DEPARTMENT OF MARINE BIOLOGY. 



133 



The trematodes found in these teleosts were further characterized by the 

 extraordinary range of form and structure they exhibited. Many of them 

 belong to new species and some to new genera which have recently been 

 established by Prof. Edwin Linton. Almost all the various subdivisions of 

 digenetic trematodes are present, distomids (including appendiculate forms), 

 monostomids, and amphistomids being all represented. Of special interest 

 also are several species belonging probably to a new genus, which were found 

 in grunts, snappers, sculpins, groupers, and slippery-dicks, and represent 

 apparently intermediate stages between the digenetic and monogenetic trema- 

 todes. The anatomy of all these interesting teleostean trematodes and their 

 morphological relationships will form the subject of a paper which will be 

 presented to the Carnegie Institution of Washington for publication. 



The species of cestodes found in the selachians examined were mostly 

 identical with those described by Professor Linton in his recently published 

 report on the Helminth fauna of the Dry Tortugas. One new and unusual 

 species, however, was found in the sand-shark, the entire body of which is 

 spinose. A species of monogenetic trematode belonging to the genus Mono- 

 cotyle was also found on the gills of the eagle ray, which is closely allied to 

 Monocotyle myliohatis, which occurs on the gills of the eagle ray of the Old 

 World. 



Preliminary Report on Studies of Grozvth, by Charles R. Stockard, Cornell 

 University Medical School, Nezv York City. 



Experiments were conducted to further test my previous results pertaining 

 to the influence of newly regenerating tissue on the animal body. The scypho- 

 medusa Cassiopea xamachana was used for this investigation. In the first case 

 each of 20 selected individuals had 5 of the 8 oral-arms amputated at their 

 bases ; another group of 20 of the same average size also had 5 mouth-arms 

 cut from each individual and in addition a piece was removed from the disk, 

 about one-third of the periphery in length and extending in radially beyond 

 the zig-zag muscular ring. Both groups were thus obliged to regenerate equal 

 numbers of mouth-arms, but the latter had also to grow new disk material 

 to replace the removed strip. Any difference in body size or vigor in the 

 two groups must be caused by the additional growth of disk material imposed 

 upon the latter group, since in all other respects the groups were in an iden- 

 tical condition. 



Measurements were made after given periods of time and tabulated. The 

 averages below show the changes in body size in millimeters : 



The second group of medus?e. which were regenerating more new tissue, 

 decreased in size more rapidly than the first group during the early 12 days of 

 the experiment. They then decrease less rapidly, so that after 20 days their 

 loss is practically the same as that of the first group. The new tissue was 

 being formed from the old body while the animals remained unfed. The fact 



