960 



EEPORT OF COMMISSIONER OF FISH AND FISHERIES. 



[34] 



much longer than diameter of bell, equal in number to the chymiferous 

 tubes. Bases swollen into a tentacular bulb. The upper wall of the 

 stomach is almost fla t or slightly convex. The ovaries are very numerous, 

 swollen, and hang down as in Polycanna (Zygodactyla) crassa, Hasckel. 

 Ko knobs between tubes on under side of the umbrella. 



Stomach walls rather broad, oval filaments sparse, short and small. 

 This species is easily distinguished. from all our ^quoridae except P. 

 (Zygodactyla) crassa by the numerous swollen ovaries thickly crowded 

 together. Unlike crasna it has a single tentacle at the extremity of 

 each tube. The specimens of P. Americana which were studied were 

 much smaller and yet had more numerous genitalia than P. crasifa. 



MESONEMA Eschscholtz. 1829. 



Mesonema CYANEUii Haeckcl. 



There are several other specimens of the family of ^quoridie, some 

 of which are simple fragments of a central disk or bell-margin, and 

 which belong to a species of Mesonema, similar to that to which the 

 name Zygodactyla cyanea was given by L. Agassiz. 



Unfortunately none of the specimens have the locality indicated, but 

 the bottles in which they are contained are numbered 9303, 9304, 9305, 

 and 9306. These are evidently all the same species, to which may also 

 be referred two other fraGiueuts from the following stations: 



The specimens of M. cyaneum are of small size as compared with other 

 Mesonema^, varying from 15-45'"'" in diameter. The species is easily 

 distinguished from others found in the (iulf Stream by the very great 

 vertical thickness of the central regit)n of the bell and its convex sub- 

 umbral central protuberance, the relatively great diameter of the stom- 

 ach, and the small size of the oval tentacles. 



The bell is composed of two regions, a central disk which has the 

 shape of a plano-convex, in one instance double-convex lens, and a 

 coronal part, a zone in Mhich lie the radial chymiferous tubes and which 

 carries on its margin the tentacles and other organs. In most of the 

 larger specimens the coronal portion is more or less broken or distorted; 

 in the smaller it is entire. The central disk is flat, slightly' convex 

 abo^'e, rounded convex below. In none of the specimens is the coronal 

 groove of great depth, although some of them have the separation of 



