V2 :\rT'SKTT:\I. lUtOOKLYX INSTI'IT'I'I': (»F ARTS AND SCTKNC'ES. 



nuclei and cell material showing; littio or no trace of cell boundaries (o, Fig. 

 15"). These are present at all sta<;es of the developins? bud, partially filling 

 the gastro-vaseular cavity, but they appear to degenei-ate in later stages, and 

 it seems possible that they serve to nourish the bud in its growth. This sup- 

 position appears the more probable from the fact that the gastro-vaseular 

 cavity of the bud is never in connection with that of tlie parent medusa (see 

 Fig. IB'') . Fig. 15'' shows a young stage of the bud wherein the entoderm has be- 

 come a cup-shaped vesicle, and the ectoderm is hollowing out to form the 

 bell-cavity. Fig. 15'' is a late stage showing that the limiting membrane, kI. 

 of the manubrium of the parent medu.sa remains unbroken, and that the en- 

 toderm of the parent medusa, ent., never comes into contact with that of the 

 bud, e n t. h. 



Netocertoides brachiatum, Mayer. 



Fi;j. 7. Plate I. 



Mateb. a. G., 1900; Bull. Mu8. Comp. Zool. at Harvard Coll., Vol. XXXVII, p. 45, FiRs. 43- 

 44 ; PI. 18. 



Bell 3.5 nun. high, mitre-shaped, walls quite thin. Sixteen hollow taper- 

 ing tentacles; one at the base of each of the sixteen radial canals. 16-25 small 

 tentacles, one or two between each pair of the long ones. Longest tentacles 

 are about one-quarter as long as the bell-height and their distal ends are 

 tightly coiled. The short tentacles are hardly more than cirri. No marginal 

 sense organs. Velum well developed. Eight main radial canals arise from 

 the manubrium, but each bifurcates, giving sixteen radial canals, which ex- 

 tend straight toward the circular vessel. The eight proximal roots of the 

 radial canals are bound to the manubrium by simple mesenteries. The 

 manubrium is broad and disk-like and the mouth is at the extremity of a 

 short neck, and is surrounded by four simple lips. Gonads within the eight 

 main radial canals. The entoderm of the tentacles, I'adial canals and nmnu- 

 brium is rosin-colored. Quite common at the Bahamas, but rare at the Tor- 

 tugas, Florida. Seen only in summer. 



Tetracannota collapsa, 51 aver. 



Fig. 32, Plate IV. 



Mayer. A. G., 1900; Bull. Mus. Comp. Zool. at Harvard Coll., Vol. XXXVII, p. 40, Fiirs. 14- 

 16, Plates 7, 8. 



Fewkes, J. W... 1883; Bull. Mu.s. Comp. Zo5l. at Harvard Coll., Vol. XI, No. 3, Figs. T, Ta. 



Mature nieduaa: Bell higher than a hemisphere and 7 mm. in diameter, 



