M. C. Mereschkowsky on the Hydroida. 323 
hope to be able to procure in England specimens of the most 
desirable species in exchange for my own, which will enable 
me to verify my determinations. At any rate, I shall attach 
a note of interrogation to any species that is in the least 
degree doubtful. The species are as follows :— 
So oO oo NAO Oe ed 
_ 
. S. tricuspidata, Alder. 
. S. rugosa, Linn. ee 
. Diphasia, Agass., sp. indet. 
. Sertularia pumila, Linn. 
. S. filicula, Ellis & Sol. 
Suborder ATHECATA. 
. Oorhiza borealis, nov. gen. et nov. sp. 
. Hydractinia, sp. indet. 
. Syncoryne Sarsti: Meduse (Sarsia tubulifera) in great 
numbers. 
. Stauridium productum. 
. Hudendrium arbuscula (?), S. W. 
. E. minimum, nov. sp. 
. Bougainvillia paradoxa, nov. sp.: the Meduse only in 
very large numbers. 
. Monobrachium parasitum, mihi (see Ann. & Mag. Nat. 
Hist., September 1877). 
. Tubularia simplex, 
. T. indivisa. 
Suborder THECAPHORA. 
. Obelia geniculata, Linn. 
. O. gelatinosa (?), Pall. 
. O. flabellata, Hincks. 
. Campanularia volubilis, Linn. 
. C. integra (?), Macgillivray. 
. C. verticillata, Linn. 
. C. neglecta, Alder. 
. Leptoscyphus Grigoriewt, nov. sp. 
. Lafoéa dumosa, Sars. 
. L. pocillum, Hincks. 
. Calycella syringa, Linn. 
. Cuspidella, sp. indet. 
. Salacia abietina, Sars. 
. Filellum serpens, Hassall. 
. Coppinia arcta, Dalyell. 
. Halecium Beanii (?), Johnst. 
. Halecium, sp. indet. 
. Sertularella gigantea, mihi, = 8. polyzonias, robust variety, 
of Sars and Hincks. 
— 
