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PROCEEDINGS OF THE 



[April, 1857- 



lated medusa-bells, traversed by four radiate tubes containing 

 within what is probably the cavity of the digestive trunk sur- 

 rounded by the sexual organ. This medusa has no tentacula nor 

 ocelli, and the digestive trunk with its enveloping sexual organ 

 fills the whole cavity of the bell. The wall of the latter is of 

 firmer consistence than is usual among free species of Endosto- 

 mata. The sexual buds situate along the sides of the branches 

 are mere ovoidal cysts containing a sexual organ, and in the spe- 

 cies about to be described, these are so large in comparison with 

 the terminal bell-shaped individuals as naturally to lead to the 

 suspicion that they are not younger stages of the latter, but male 

 medusas, which do not need so great a development of the bell, 

 since they are not intended to nurse embryos. 



PHYSALIA AURIGERA, nov. spec. 

 The basal vesicular medusa measured in the largest specimen, 

 I have examined about six inches longitudinally. Its height was 

 about three inches. Its gemmiparous extremity is very much more 

 inflated and rounded than the opposite pore-bearing pole. The 

 posterior knob which sometimes appears to be divided ofTby a slight 

 constriction as a distinct portion of the bladder, is rather over an 

 inch in length. The pore is, not situate at the extremity of the 

 bladder, but at a very considerable distance behind it, and instead 

 of being on the median line, denoted by the direction of the crest, 

 is on one side of it, which according to those who consider this 

 extremity anterior, would be the left side of the median line. 

 The crest originates about a horizontal inch behind the inferior 

 or budding extremity of the bladder, and extends backward to 

 within nearly the same distance from the opposite or superior ex- 

 tremity. The descending internal partitions are alternately long 

 and short, and vary in number according to the size of the speci- 

 men, the largest number counted being sixteen and the smallest 

 nine. These partitions are longest and the intervening spaces 

 greatest about the middle of the crest, becoming smaller as we 

 approach its extremities. If we consider the crest as marking the 

 mesial line, we must consider the racemose cartilaginous rep- 

 resentative of the digestive trunk, which has an elongated, 

 almost linear form, as placed obliquely,* the angle which it makes 



* This of course must be considered as entirely a special description ; for the 

 crest, horizontal as it is in Physalia, is probably in a general way homologous with 



