MUSEUM OF COMPARATIVE ZOOLOGY. 267 



A. elegans. A characteristic feature in their anatomy is the prolongation of the 

 upper wall of the hell cavity into two symmetrically placed recesses (h ?i), one 

 extending into each of those prolongations of the nectoealyx which embrace 

 the axis. The sides of the swimming-hell, on the external surface, are sparingly 

 covered with papillae which are enlarged at their ends into a spherical knob 

 formed of large thread-cells (PI. VI. fig. 27). 



The covering-scales are more rectangular in outline than those of A. elegans, 

 and are crossed by several longitudinal ridges (/) bearing lasso-cells closely 

 crowded together. Their exact shape was not determined, as only two speci- 

 mens were taken, and these were evidently larval. The sides and outer convex 

 surface of the bract bear the characteristic papillae which have been spoken of 

 as found on the walls of the nectocalyces. 



The tastern (d d' d'') are more slender than those of A. elegans, and have a 

 greater flexibility of motion. Their extremities protrude far outside the limits 

 of the covering-scales, and their very tips are armed with clusters of lasso-cells. 

 From the base of each there hangs a long, flexible, highly contractile filament (e), 

 which is commonly carried retracted at its base near the axis. 



There is but one feeding-polyp, which appears to be the metamorphosed 

 yolk mass, and is found at the lower end of the axis. The single tentacle (/) 

 suspended from its base bears tentacular knobs (k) like those of A. elegans. 

 Immature pendants (j) in all stages of growth are found at the base of the 

 polvpite, on the wimperwulst. The tentacular knob is composed of a coiled 

 sacculus of dark red color, enclosed in an involucrum and terminated by a 

 vesicle and two lateral filaments. These filaments are short and stunted, and 

 seem to indicate that the specimens studied were immature.* No sexual bells 

 were observed. 



Agalmopsis fragile, sp. nov. 



Plate V. Fig 2. Plate VI. Figs. 16, 17, 23, 24, 25. 



In 1878 Claus f described from Trieste a new Physophore, to which he gave 

 the name Halistemma Tergestinum. Metschnikoff refers the same, taken at 

 Villa Franca at about the same time, to Stephanomia picta, sp. nov. Metsch. I 

 have already discussed X the synonomy of this genus. 



A single specimen of an Agalmopsis closely related to S. 2>icta, Metsch. (//. 

 Tergestinum, Claus), was found at Key West. So close is its likeness to the 

 Mediterranean species that it is probably the same. Direct comparison is 

 necessary to prove their identity. 



* This species is very different from A. elegans of about the same ago. A. 

 with one polvpite has tiro kinds of tentacular knobs and a prominent network of red 

 pigment on the feeding polyp. It is destitute of the papilla found on the necto- 

 calyces and scales of A. papillosum. 



t Ueber Halistemma Tergestinum, n. sp., in Arbeit, d. ZooL Inst, in Wien, 

 Heft I. 



\ Bull. Mus. Comp. Zool., VI. 7. 



