64 IIYDROID.E. 



tenth of an inch in height, the arrangement of the tentacles is totally 

 difierent from that of the adult. They are as yet not arranged in clus- 

 ters, but placed at regular intervals in one line on the edge of the disk. 

 No difference can at present be detected between the anchors {a, Fig. 

 90) and the tentacles (t, Fig. 90) of the disk, showing plainly that the 

 anchors, as Professor Clark has proved, are only modified tentacles ; the 

 peduncle is also quite short, and stout in proportion to the disk. The 

 young Lucemaria is in this state a close representative of the genus 

 Carduella of Allman, which may possibly prove to be only the 3'oung 

 of some European species. 



Greenland (Steenstrup) ; Anticosti (Verrill, Shaler, and Hyatt) ; 

 Massachusetts Bay (H. J. Clark). 



Cat. No. 320, Nahant, Mass., A. Agassiz, May, 1862. 



Cat. No. 321, Chelsea Beach, L. Agassiz. 



Cat. No. 822, Mount Desert Lslands, Maine, W. Stimpson. 



Cat. No. 323, Anticosti Island, Anticosti Expedition, August, 1861. 



Cat. No. 380, Anticosti Island, Anticosti Expedition, August, 1801. 



HaUclystus salpinx H. J. Clark. 



HaUclystus salpinx H. J. Clark. Journ. Bost. Soc. Nat. Hist., p. 563. 1863. 



Mount Desert Islands. Maine (Stimpson). 



Order HIDROIDiE Johnst. ('»orf. agass.). 



Anthnzoa Iliidrnida JonxsT. Brit. Zoopli., Soooml Edition, p. 5. 



Oi/miuiplil/ialmd Forbes. Brit. Naked-ejed Mudiisa?. 1848. 



Comlliiirid Tahulata, Rugnaa, and Ilijdraria MiLXK Edw. & Haime. 



Hi/ilmiimliiKfc et Siphonophnrie VocT. Sipli. de Nice. 



Ilijdrnhlcn, ^ft'l!u.1if/a Craspcilohi, an<l Siphoitophnra Gegenb. Zeit. f. W. Zool. 185G. 



Hi/druiilceUcCR. (p. p.). Proc. Elliot Soc. 1857. 



Hyilrozoa Ilr.VL. Ray Soc. IS.'Jt). 



Hydroida: AoASS. Cont. Nat. Hist. U. S., HI. 18G0. IV. p. 337. 



From want of materials, no writer on Acalephs has thus far attempted 

 to make use of the einbryological characters noticed in the develo]imont 

 of young Hydroid Medusiu and of the young Hydraria. From the ob- 

 servations of Wright on the development of Thmimantias inconsjnaia, 

 of ^Equorea, and from what I have had occasion to observe myself on 

 the Hydroid of Melicertum and of Tima, we have acquired sufficient 

 information to .satis{[y ourselves that Tubularian-like llydroids stand 

 lower than the Campanulariaus ; while such forms as the Hydroids of 



