312 



BULLETIN 100, UNITED STATES NATIONAL MUSEUM. 



so characteristic of other aequorids are absent; and the absence of 

 papillae has now been established in so many specimens that it may 

 be assumed to be constant. 



Unfortunately only two of the specimens have the entire margin 

 intact; on them only was it possible to make certain of the entire 

 number of tentacles. But judging from the number of canals in 

 the damaged specimens and their relation to the remaining tentacles, 

 the proportional numbers listed below can not be far from the truth 

 for the entire series. In the following table the numbers of ten- 

 tacles and canals are given for all recorded specimens which are 

 described as having no excretory papillae. I previously referred 

 Polycanna purpurostoma of Agassiz and Mayer to pensile. But 

 fresh examination of their type specimen revealed papillae, as well 

 as that the tentacle bulbs clasp the exumbrella. 



Locality. 



Philippines 



Maldives, Brown 



Do 



Do 



Do 



Tahiti, " Rhegmatodes lacteus " 



Agassiz and Mayer 



" Siboga" Maas 



Do 



Diam- 

 eter. 



50 

 22 

 45 

 60 

 60 

 60 



50 

 100 

 90 



Diam- 

 eter of 

 stomach. 



Ten- 

 tacles. 



43 



50-60 

 50 



13 

 11 

 10 

 H) 

 15 

 13 



10 

 16? 

 10? 



Tentac- 

 ular 

 bulbs. 



210 

 85 



250 



Canals 

 of all 

 sizes. 



and ages. 



162 

 124 

 120 

 i 100 

 • 150 

 148 



105 

 1200 

 1250 



Proportional 



numbers. 



i About. 



Vanhoffen (1911, 1912, 1913) has given tables for much larger 

 series, all characterized by many more canals than tentacles. But 

 as he does not state whether his specimens had or lacked excretory 

 papillae, it is a question whether they belong to pensile as here defined 

 or whether some of them may not have been macrodactylum, or even 

 Ae. aequorea. 



As far as our knowledge yet goes, there are usually at least 10 times 

 as many canals as tentacles in large specimens of pensile, and seldom 

 over 12 times as many. But it is quite possible that pensile may, in 

 development, pass through what we may call a " macrodactylum " 

 stage with respect to the proportional numbers of these organs. 



Browne (1904) has already called attention to the prevalence of 

 anastomosis among the canals of pensile. It is a prominent feature 

 in the present series, especially near the distal extremities of the 

 canals. 



The otocysts are very numerous ; about as much so as tentacles and 

 bulbs combined in the one specimen in which they seemed to be intact 

 in about the normal condition. 



