294 



L. J. THOMAS. 



ternal lithocysts upon the bell margin between the tentacles." In 

 characterizing the genus Cubaia (page 351), he states that there 

 are "lithocysts projecting outward as in Gonionemns". . . 

 " this genus is closely related to Vallentinia Brown 1902 but in 

 Vallcntinia the lithocysts are enclosed and on the inner side of 

 the margin, whereas in Cubaia they are external and on the lower 

 side of the margin between the tentacles." The plates of the 

 same monograph are just as confusing as the foregoing descrip- 

 tions in the manner in which the otocysts are located. Otocysts 

 are shown as distinct projections from the external margin of the 

 bell in Fig. i of Plate 45, though Fig. 2 of the same plate and 

 Fig. 3 of Plate 46 correctly portray them embedded in the meso- 

 glea as outgrowths from the ring canal. 



The location of the otocyst within the mesoglea and the orienta- 

 tion with reference to other structures is shown in Fig. I, 

 Plate I. 



RELATIONS OF OTOCYSTS TO TENTACLES. 



Hargitt (1910: 249) referring to the location of the otocysts, 

 says : ' Normally they should occur in somewhat symmetrical 

 order between the bases of the tentacles. This, however, is rarely 

 the case." Mayer (1910: 342) gives the number of tentacles for 

 specimens of G. vert ens 15 mm. in diameter as 60 to /o but it 

 appears that his count is too low. In the following table are 

 given the data regarding the numbers of otocysts and tentacles in 

 part of the material studied in the present investigation. 



TABLE I. 



RELATIVE NUMBERS OF OTOCYSTS AND TENTACLES IN GONIONEMUS. 



