54 



THE MUSEUM. 



The Medusae. 



Among the most interesting and, to 

 me, the most beautiful of all marine 

 animals are the Medusa'. Their deli- 

 cate construction and the beautiful 

 tints which some of them possess 

 make them especially attract- 

 ive. But as will be seen further on, 

 a few species, like some other animals, 

 are more beautiful at a distance. 



In general outline the Meduste re- 

 semble very closely the mushrooms. 

 An organ similar to the stalk of a 

 mushroom is present and is called the 

 "manubrium," while the umbrella- like 

 top of the mushroom is almost identi- 

 cal in appearance with that of the 

 jelly fish. This disc is called by reas- 

 on of its likeness the "umbrella," 

 Some of the species posses a large 

 quantity of tentacles which are sus- 

 pended from the outer edge of the 

 umbrella and vary from short filaments 

 to streamers many feet in length. 



The shape of the "umbrella" varies 

 considerably but in all its variations 

 resembles the different shapes of the 

 mushrooms. 



The Medusa; vary in size from that 

 of a pea to specimens the size of a 

 large umbrella. 



All the streamers are provided with 

 organs called lasso cells which contain 

 a poison more or less virulent. Upon 

 being touched the jelly fish shoot out 

 threads from these lasso cells which 

 paralyze the object pressing upon 

 them. Each of these cells serves but 

 once. When ruptured they disappear 

 by absorption and are replaced by 

 new cells. 



I have collected and handled many 

 hundred Dactyloiiictra quiinjuccirra, 

 a common species, of all sizes when 

 fresh from the water and have never 

 suffered any inconvenience other than 

 a slight itching which might be felt for 

 a few hours; but recently I observed a 

 report of a severe case of blood-pois- 

 oning, in a local paper, which was at- 

 tributed to the same species. 



Physalia pclagica, a jelly fish of 

 tropical and semi-tropical seas, which 



is occasionally driven north, can cause 

 considerable pain as I have learned 

 by experience. During the past sum- 

 mer I collected a few at Sakonnet Pt., 

 R. I., and being obliged to handle one 

 specimen longer than was proper, was 

 severely stung. The pain, which was 

 very acute, lasted about si.x hours, 

 and I would advise ail collectors, if 

 they should happen upon a nice speci- 

 men unexpectedly (as I did) and are 

 without collecting apparatus to use 

 their hat for a pail or leave the "beau- 

 tiful thing" alone. 



The method by which the Medusa; 

 obtain food is very simple. Upon 

 coming in contact with any substance 

 recognized as suitable for food it is 

 immediately attacked and paralyzed 

 by the threads from the lasso cells and 

 is then enwrapped by the jelly-like 

 body of the Medusa; until digested. 

 The jelly fish are capable of motion 

 and at times move quickly, though 

 they usually fioat up and down with 

 the tides. 



D. quinquccirra is one of the com- 

 monest varieties and during the sum- 

 mer months is very abundant in the 

 waters of Narragansett Bay, R. I. I 

 have usually found this species at a 

 depth of about three feet, though they 

 float both deeper and nearer the sur- 

 face. They will frequently sink when 

 the boat passes over them which 

 would seem to indicate that they are 

 influenced by light, as I have often 

 passed over them with this result, 

 when the boat was floating with the 

 current without making a ripple on 

 the surface. 



The remains of jelly fish which have 

 been left on the shore by the receding 

 tide are often seen. In a few hours 

 what was once a jelly fish, weighing 

 perhaps two pounds, will beconic, 

 when exposed to the heat of the sun, 

 a bit of scum weighing thirty or so 

 grains. 



Goodrich in speaking of their re- 

 production says: "These animals 

 [the Medusa] are all unisexual and 

 propogate by eggs, which the female 



