78 THE MEDUSAE. 



This widely distributed species was taken at eleven stations. All the spe- 

 cimens are small or medium sized. Unfortunately many of the specimens 

 were so battered that it was impossible to count the otocysts, but this could 

 usually be done in one or more quadrants. In the smaller specimens the 

 number per quadrant is two, eight in all. In larger specimens there are 

 three or four per quadrant, as Maas (:06'') and Browne (: 05'') have already 

 observed. The increase is, however, irregular, there being often different 

 numbers in the different quadrants of a single specimen, as is seen in several 

 cases in the above table. 



Aeginura Haeckel, 1879. 



sens. em. Maas (:04", :05). 



Cunoctona Haeckel (79). 

 Aeginodiscus Haeckel ('79). 



Aeginidae with eight tentacles and sixteen (or thirty-two) gastric pockets ; 

 with secondary tentacles situated on the margins of the lappets. 



This interesting genus of Narcomedusae, since its discovery, has been 

 described twice by Maas, from the collections of the Prince of Monaco (: 04'') 

 and from those of the " Siboga " expedition (: 05). Maas has been able 

 to study the anatomy in such detail that I can add but little to his account 

 from the rather fragmentary specimens in the present collection. The most 

 interesting feature of this genus is the presence, demonstrated by Maas (: 05) 

 on the " Siboga " specimens, of a series of secondary tentacles (three per 

 lappet) on the bell margin. These are solid, with endoderm core, and are 

 connected with the vascular lamella (: 05, p. 79). They are not known to 

 occur normally in any other Narcomedusa, but I have found that such a 

 secondary tentacle may sporadically replace an otocyst in Pegantha smar- 

 agdina (p. 91), evidence supporting the essential identity of otocysts and 

 tentacles in this group. Otocysts are also present. Specific diagnosis of 

 the members of the genus is uncertain, because the specimens both of the 

 " Challenger" and of the Prince of Monaco were rather fragmentary. There 

 seems no doubt that the surface form, A. lanzerotae Haeckel, is distinct from 

 the two or three intermediate species, since it differs from the latter in the 

 form of the stomach, presence of a proboscis, and especially in lacking 

 the very characteristic endodermal pigmentation. Moreover, it is doubtful 

 whether it has the secondary tentacles on the bell margin, for Haeckel saw 

 no such structures, although he studied living specimens ('79, p. 318). 



