TUBULARIA CRISTATA. 417 



GONOSOME. — GoxopuoRES in ten or twelve pendulous racemes, which are 

 disposed in two or three rows one over the other, and which surpass in lenglli tlie 

 proximal tentacles of the hydranth ; female gonophores with from six to ten laterally 

 compressed crest-shaped, hollow tentaculiform processes ; male gonophores destitute of 

 processes ; radiating and circular canals absent. 



Colour. — Perisarc light yellow ; generative mass deep yellow, on both male and female 

 gonophores. 



Deveiopiiiciit of Gonosoiiie. — Sunnner and autumn. 



Habitat. — In brackish water, attached to floating timber, &c. 



Locality. — Boston Harbour, Prof. Agassiz. 



The present species is referred by Agassiz to one of those separate genera into which he has 

 broken up the genus Tuhularia of the European zoologists. He here substitutes for Tuhularia 

 his new genus Pari/pha, but, in consequence of the want of a definite diagnosis in his description of 

 the hydroid, it is by no means easy to perceive the exact characters which he would select as 

 those entitling it to the rank of a separate genus. He appears, however, to find them in the 

 absence of gastro-vascular canals, by which the sporosacs of the present species are distinguished 

 from the sporosacs of those species which, along with the European Tuhularia indivisa, he would 

 still retain in the old genus Tuhularia ; and in a peculiarity of the tentacida-like processes with 

 which the female sporosac is crowned, and which he believes sufficient to separate the present 

 species from those which he would place, along with the European Tuhularia, lari/iir, in his new 

 genus Thamnocnidia . 



Tuhularia crocea has not yet been found on the European side of the Atlantic. It is 

 described by Agassiz as growing in great luxuriance on floating timbers in Boston Harbour, 

 where the sea water, even at high tides, contains a large admixture of fresh water from the river. 

 It affords the subject of one of the beautiful plates in the ' Contributions to the Natural History 

 of the United States.' 



*^* 16. TuBULAKTA CRISTATA, JP Cradi/. 



TuBULARiA CRISTATA, — M'Cradij, in Proc. Elliott Soc. of Nat. Hist., vol. i, p. 156. 

 Parypha CRISTATA, — Agussiz, Contr. Nat. Hist. U. S., vol. iv, p. 342. 



TROPHOSOME. — Htdrocadlus attaining a height of from two inches to nearly 

 three inclies.^ Hydranths slender, the basal portion " not much exceeding in 

 diameter the width of the portion above it ;" twenty or more tentacles in the proximal 



M'Ciady does not state wliether iiis Tubuluria crislata is a simple or a branched form. 



