PORPITA. 331 



25 mm. in diameter, on which Eschscholtz noted the well-marked tubercles 

 on the upper surface of the disc, which since prove to be a verj- important char- 

 acter. Afterward, another Pacific species, P. radiaia Brandt, was recorded, 

 with only a very cursory diagnosis. 



The accounts of P. pactfica Lesson, and P. radiaia Brandt, based as they 

 are on such trivial features as size, color, and the form and length of the tentacles, 

 contain nothing to show that they are not identical with P. coerulea Eschscholtz. 

 The localities of capture add further support to such a union. P. ramifera 

 Eschscholtz likewise comes under the same category, as a young stage of coerulea. 

 To the combined species thus formed, the oldest name, P. pacifica Lesson ('26) 

 must be applied. P. paciUca has recentlj' been recorded by Agassiz and Maj-er 

 (:02) and by Mayer (:06) from the Tropical Pacific, and from the Hawaiian 

 Islands. 



The case of P. chrysocoma is less clear, inasmuch as the bright yellow coloi' 

 of limbus and tentacles figured and noted by Lesson ('30) differs markedly from 

 the brilliant blue of these parts in the Pacific specimens which I have examined 

 in life. In P. umhella, however, I have found that these regions may appear 

 yellowish in certain lights and against certain backgrounds. The locality of 

 capture of chrysocoma, close to New Guinea, suggests that it was probabh' identi- 

 cal with the "iSiboga" specimens from the Malaysian region studied by Lens 

 and Van Riemsdijk, and referred bj^ them to P. umbella. 



Finally, to conclude our survey of the Pacific species, we must examine 

 Haeckel's two species, Porpita fungia and Porpitella pectanthis, both of which 

 were described and figured in detail. The two are placed l)y him in separate 

 genera on the supposition that the tentacles in Porpita are evenly distributed 

 over the tentacular zone, but arranged in groups in Porpitella. In the latter 

 genus he includes P. coerulea Lesson and P. radiaia Brandt. This separation 

 is exactly analogous to the distinction drawn by him between Porpema and 

 Porpalia (p. 323). Porpitella is the young of Porpita; and I may note that 

 exactly similar stages have been long known for P. umbella (A. .\gassiz). Since 

 Porpitella pectanthis and Porpita fungia were both taken in the same general 

 region of the Pacific, it is almost certain that they represent two stages in the 

 growth of but a single species. 



A comparison between Haeckel's description of P. fungia and Eschscholtz's 

 account of P. coerulea shows such close resemblance between the two, especiall}' 

 in the presence of prominent tubercles on the upper surface of the float, that I 

 have no hesitation in uniting them. All Porpitas, then, as yet known from the 



