216 THE MEDUSAE. 



Unfortunately the label on the Behring Sea specimen gives no information 

 as to the depth from which it was taken, but at the station where it was 

 captured the depth is only 121 fathoms. If the surface is its usual habitat, 

 and its occurrence there not merely sporadic, its horizontal range is remark- 

 able in extending from tropical to cold waters. 



Heterotiara Maas, 1905. 



sens. em. 



Bythotiaridae with four simple radial canals ; with only short blind 

 canals if any ; gonads purely interradial, without tranverse folds. 



The collection contains two specimens which agree very closely with the 

 provisional genus Heterotiara proposed by Maas (: 05) to include a single 

 immature specimen in the "Siboga" collection. In this specimen the four 

 canals were unbranched ; but Maas has suggested that inasmuch as the 

 gonads were but slightly developed, branching might later appear. Since 

 the present specimens, both of which are sexually mature, have unbranched 

 canals, it is evident that in Heterotiara the simple condition of these struc- 

 tures is permanent. Neither are there any blind centripetal canals, such as 

 are developed in Sibogita. 



The true specific relationship between the present and the " Siboga '' 

 specimens is hard to determine, because of the immaturity of the latter; 

 but inasmuch as the differences between the two appears no greater than 

 can be readily accounted for as due either to individual variation, or to dif- 

 ferences in the stages of growth, I include the present specimens under 

 Maas's species H. mvonyma. 



Heterotiara anonyma Maas. 



Heterotiara anonyma Maas, : 05, p. 19, taf. 3, figs. 19-21. 



Plate 41, figs. 12, 13. 



Station 4650 ; 300 fathoms to surface ; 1 specimen. 



Station 4652 ; 400 fathoms to surface ; 1 specimen. 



The two specimens are of about the same size, 22 mm. high by 20 mm. 

 broad, and both are in fair condition. As in the "Siboga'' specimen the 

 bell is high, the gelatinous substance thick at the apex; but there is no 

 apical projection. 



Tentacles. — In one specimen there are eleven tentacles, in the other 



