MUSEUM OF COMPARATIVE ZOOLOGY. 155 



The development of the egg of Turritopsis is unknown. Eggs were ob- 

 servcfl to be drojjped in August. The younger stages of the medusa are 

 characterized by the tenuity of the bell walls, and the shoi't tentacles, which 

 are sometimes carried stitUy thrown back along the side of the bell or tightly 

 coiled round the tentacular bulbs. 



Dipurena strangulata, McCeady. 



Plate IV. Fig. 5. 



Two species of Dipurena, D. strangulata and D. cervicata, were described 

 from Charleston Harbor by McCrady, who founded the genus. A third 

 species, D. conica, is described from Naushon, Vineyard Sound, by Mr. 

 Agassiz. 



A single specimen of D. stranrjulata was captured by the author at Newport, 

 in September. The bell is half-egg-shaped, with the minor axis greater than 

 the height. It is very transparent, colorless, and has a smooth surface. Ka- 

 dial tubes four, resembling fine lines on the bell, and simple in profile. Pro- 

 boscis long, slender, extending when protruded far outside the bell opening, 

 and with ovaries so distended with eggs that it can with great difficulty be 

 withdrawn into the bell cavity. At the point on the inner surface of the bell 

 from which it is suspended, there is an enlargement in the neck of the probos- 

 cis into a kind of bulb, which has bright red contents. The function of this 

 bulb is not known. A similar structure, reduced in size, is found in many 

 other medusae, as in Sarsia mirabilis, Ectopleura ochracea, and some others. 

 The sexual organs are divided into two parts, or arranged in two packets on 

 the proboscis, separated by an interval from each other. The upper of these 

 is placed about midway between the buUi already mentioned and the mouth 

 or the distal end of the proboscis. This division of the sexual organ is a 

 simple oblong body of uniform size throughout. Through the external walls 

 the motion of the chymiferous fluid within the proboscis can be well seen. 

 The enlargement around the cavity of the proboscis is filled with ova. The 

 upper portion of the surface is covered with minute warts, the lower bears 

 patches of bright crimson color. The whole has a greenish color throughout. 

 The lower of the two divisions into which the sexual' glands are divided is 

 larger than the former, and has a slight constriction midway in its length. In 

 it also, as in the former, the walls of the stomach may be easily seen, sur- 

 rounded by the peripherally placed eggs. Like the lobe already mentioned, 

 it too has patches of crimson color in its lower half, and the surface is set 

 with lasso-cells (?). The mouth is simple, and destitute of tentacles or knob- 

 like appendages. The tentacles are short, stiff, solid, or with a very small 

 central Ciivity, and are generally carried at an angle to the bell. They are four 

 in number. The tentacular bulb is large, spherical, with green pigment, and 

 a single small black ocellus externally placed on a slight projection from the 

 bulb. The distal end of the tentacle is a dumb-bell shaped organ, which is 



