218 BULLETIN OF THE 



into the formation of the tentacular knob are the peduncle, the involucrum , 

 the sacculus, and the terminal filament. 



The terminal filament {ft) is long, thread-like, single, arising from the 

 distal end of the sacculus. In its walls are imbedded many lasso-cells, or 

 uematocysts. The sacculus is closely coiled in several turns. It is a large 

 reddish body, armed with batteries of lasso-cells, and crossed by prominent 

 lines. 



The involucrum {inv) forms a cap over the sacculus.* It is bell-shaped, 

 with entire edges, the sacculus {sac) arising from the inner central point. 

 The whole tentacular knot hangs from the tentacle by the peduncle. 



Tasters.] — Among the most interesting and it would seem exceptional struc- 

 tures in the genus Nanomia are those organs which are known as tasters (lit'). 

 The most marked peculiarity in their anatomy is the existence of an "oil 

 globule " (og) near their base. 



The tasters hang from the polyp-stem midway between the polypites. A 

 single adult and many half-developed tasters occur between each pair of polyp- 

 ites. Individual tasters are small, slender, flask-shaped bodies, resembling 

 immature polypites. They arise directly from the stem' and are destitute of 

 a basal peduncle. The distal extremity is closed. 



Each taster bears near its attachment a prominent red body of spherical 

 shape, known as the " oil globule." The taster has a single long tentacle Qi ta), 

 destitute of lateral appendages. In the water in which Nanomia was kept 

 alive, several tasters which had separated from the main stem were found 

 floating about near the surface. These were not seen to grow into colonies of 

 Nanomiae, but gradually became opaque and decayed, never in those studied 

 growing into new colonies. 



tronophores. — A. Agassiz supposea uuai. sepai aie male or female colonies of 

 Nanomia were found. He considered that some colonies of this genus are all 

 males, while others are all females. My observations diff"er in this respect 

 from his. The adult Nanomia, like the genus Agalma, has male and female 

 bells on one and the same colony. 



The sexual bells (g) of Nanomia are found near the oase of the tasters, 

 where they form botryoidal clusters. These clusters occur on all parts of the 

 polyp-stem wherever hydrocysts are found. The interior of the male bells in 

 many cases has a milk-white color, while the female bells are always trans- 

 parent. Each male gonophore is bell-shaped and fastened to the base of the 

 cluster by a short flexible peduncle. The walls of the bell are thin, with four- 

 radial tubp« joined to a marginal canal. The peduncle is penetrated by a 



* The name sacculus has been given to the coiled red structure which forms 

 the larger part of the knob by otliers. It seems more natural simply to inter- 

 change the ternas, so that what is now called the involucura may be known as the 

 sacculus, and vice versa. 



t The term " taster," used to designate these structures, is open to some objec- 

 tions, but is regarded as one of the best which has been suggested to apply to these 

 peculiar organs in the Physophores*' 



