314 PROCEEDINGS OF THE NATIONAL MUSEUM. 



NARCOMEDUS^E. 



The collection contains only one species of this order, ^ginoj>sis 

 laurentii Brandt. 



iEGINOPSIS LAURENTII Brandt. 

 Plate 32, figs. 2-6. 

 JEginopsis laurentii Brandt, '38, p. 363, pi. 6. 



Fogo Island, Newfoundland, July 28, 43 specimens, 1.5-7 mm. in 

 diameter; Gready Harbor, Labrador, 1 specimen, 6 mm. in diameter; 

 30 miles southeast of Nain, Labrador, 1 specimen, 4 mm. and 1 speci- 

 men 13 mm. in diameter, the latter with well-developed gonads. 



Though often recorded, certain anatomical features of this species 

 are still imperfectly known. Especially is it desirable to determine 

 whether or not a canal system is present, inasmuch as this point has 

 never been examined in serial sections, although Maas (:06) has 

 noted that surface views give no indication of the presence of either 

 ring or peronial canals. 



In general appearance the older specimens (pi. 3, fig. 2) closely 

 resemble the figures given by Brandt ('38, pi. 6), the bell being of 

 moderate height, and the tentacles arising fron the exumbral surface 

 at a very high level. 



Tentacles. — The most important feature of this genus is the fact 

 that while there are only four tentacles, there are eight peronise, a 

 fact clearly shown in Brandt's figures and accepted by all later 

 authors. 



Gastrovascular system. — The condition of the gastric pockets has 

 been figured by Brandt ('38) and described by Maas (:06) (pi. 32, 

 figs. 2, 3). 



The series shows strong evidence that the sixteen gastric pockets 

 of the adult are derived by subdivision from eight primary perradial 

 pockets, one opposite each peronia. In the youngest specimen in 

 the series, 2 mm. in diameter (pi. 32, fig. 4), the condition is as follows: 

 opposite each of the four tentacles the primary pockets are bifid, 

 but opposite the four peronia^ without tentacles the pockets are 

 undivided, exactly as they are in the Cunanthidse. At a slightly 

 later stage (specimen 3 mm. in diameter) these latter pockets have 

 become subdivided by shallow radial notches at their outer margins. 

 Finally as growth proceeds a condition is reached (pi. 32, fig. 2) in 

 which all eight primary gastric pockets are bifid to the same degree. 

 Judging from these two stages it is reasonable to assume that there 

 are originally four pockets opposite the tentacles, only that in their 

 case the bifid condition is attained earlier than in the four pockets 

 opposite the peronia? without tentacles. 



