122 THE OCEANIC HYDROZOA. 



strife were counted, and tliese had little tubercles (zacken) disposed along their length. The 

 blue limb is a line and a half broad. 



With a strong magnifying power it ma}' be observed' that the outer edge of the limb 

 (equal to one fifth of the whole) is marked by fine excentric darker striae, which may be 

 regarded as muscular fibres, by whose aid the marginal limb may be bent upwards or 

 downwards. The rest of the limb appears dotted. Tiie bluish tentacles gradually thicken 

 towards the ends, where they are trihedral, and their outer half is beset with three series of 

 almost stalked capitala. The tentacles vary in length, the largest surpassing the diameter 

 of the body, the shortest not projecting further beyond the limb than its breadth. In a large 

 and uninjured specimen there were seven series of tentacles of different lengths. 



The gonoblastidia are whitish and bluish, as in the preceding species. The bodies, 

 whicli appear to be germ-receptacles, have the appearance of yellowish-brown (hellhornfiir- 

 bigen) racemes. The largest specimens attain the diameter of an inch. 



It chanced that I fell in with Porpita only once during the cruise of the " Rattlesnake," 

 and the observations I made are of no moment. But some very large Forpita, which, though 

 tiiey have long been preserved in spirit, are in very good preservation, having recently come 

 under my notice, I am enabled to add some particulars of interest to what is already known. 



Tiie proximal or superior face of the disc in this species is quite flat, and measures, 

 including the limb, about one inch and a half in diameter, but its thickness does not exceed 

 one thirteenth of an inch. The limb, one eighth of an inch wide, is thin and flexible. The base 

 of the large central polypite measures not more than one quarter of an incli in diameter, so 

 that it occupies but a very small portion of the distal or inferior face of the disc. The small, 

 or gonoblastidial, polypites are exceedingly numerous, occupy an area half an inch wide 

 on each side, and, when distended with food, as many of them are, they acquire a transverse 

 diameter of one eighth, and a length of one fourth, of an inch. The space between the zone 

 occupied by these polypites, or the gonoblastidial zone, and the limb, is occupied by a narrow 

 area, rather less than one eighth of an inch wide, which presents a reticulated appearance, 

 and to which the numerous rows of tentacles, almost all of which were detached in my 

 specimens, were attached. 



This tentacular zone, as I will call it, is somewhat convex downwards and outwards, 

 while the rest of the inferior surface of the disc is flat. 



It is impossible to say what may have been the original coloration of this species. 

 At present, all my specimens have a uniform pale-yellowish hue, which inclines to brown 

 over the gonoblastidial area. The proximal surface of the disc is covered with numerous 

 small tubercles, set at irregular intervals, and remarkably large and prominent in the central 

 region, while they become smaller and less conspicuous peripherally. 



The presence of these tubercles leads me to think that this species may be the 

 Porpita cwrulea of Eschscholz, which is, perhaps, identical with the Porpiia Atlanficn of 

 Lesson ('Acalephes,' p. 590).^ 



With respect to the general character of the polypites, the gonoblastidia, and their buds, 

 I have nothing of importance to add to the account given by Kolliker, except that the roof of 



^ There is no means of ascertaining whence the specimens were obtained. 



