90 



AMERICAN HYDROIDS. 

 Free portion of mesial nematophore longer than width of hydrotheca. 



Marginal ,. DDl u ,-., i,,,mi DB - Aperture nearly hori/.outal. Corbula closed. 



Aperture at an angle of nearly 45 with axis of hydrocladium^ 



contorta. 



Hydrotheeal keel present: 

 , Keel broad. Rootstock distinctly and regularly annulated .. minute. 



horizontal septal ridge. Two strong Colon'y mow ttMl^nehhigh ! 



processes below th, base of each hydro- Xo hvar(>t - h(Jral keel . 



Cladium, on tront .,1 stem. Mn:,,!,, Hydrotheca almost cylindrical mini,,,,,. 



Hydrotheca obconica! perforata. 



Upper portion of hydrotheca free simples . 



Mesial nematophore long, adnato, reaching i 



nearly to top of hydrotheca, without ( Marginal teeth moderately long atlmani. 



internal septal ridge. Marginal teeth Marginal teeth very long robasta. 



even and regular. Allmanl group. 



Mesial nematophore not reaching near top of hydrotheca rathbuni. 



"lesial nematophore expanded and reaching decidedly above top of 



hydrotheca. latirostris. 



Mesial nematophore tubular, and reaching decidedly above top of 



"stis? "SEiTsr "'"" -Sn"' '"* ^^:e SSS 



Colony not more than 'A inches high. One hydrotheca between corbnla 



and stem ...... . ... . .octvcttrptt,- 



Mesial nematophore very short. Anterior tooth very long. . .i/ravillimu. 

 T\\ olong anterior teeth patugoiiica. 



Margins of hydrotheca" almost smooth and crenate crenata. 



Margin with 8 to 10 teeth; mesial nematophorcs near center of hydro- 

 theca' MJida. 



Margin smooth; mesial nematophore aduate to front of hydrotheca. 



trieuepis. 



t'dis { Three hydrocladia borne on each interuode of stem conntrii'la. 



Hydrotheeal aperture almost vertical ; mesial nematophores very long 



and tubular xarii/ni/una. 



Mesial nematophore double hiroriuila. 



Colony small, pelagic on gulf-weed, characters not determiuable. 



ptlagica. 



AGLAOPHENIA RHYNCHOCARPA Allman. 



, Plate XVIII, figs. 1,2.) 

 Aijlaoplienlu rliynchorarpa ALLMAN, Mem. Mns. Coni]>. /Cool., 1877, V, No. 2, p. 40, pi. xxin. 



omt'. Colony usually unbranched, attaining a height of about -i inches; stem not 

 fascicled, divided into regular internodes which are more apparent in the distal than in the proximal 

 portion, each of which bears a hydrocladium near its distal end; hydrocladia alternate, rather 

 close together, divided into regular internodes, each of which is itself divided by internal septa 

 or ridges into about flve communicating chambers. Hydrotheca' closely approximated, robust, 

 with the anterior profile strongly concave above the mesial nematophore; aperture oblique, margin 

 with about eleven regular teeth. There is a shallow keel in front which projects above the 

 marginal teeth, and a strong oblique iutrathecal ridge parallel to the mesial nematophore. 

 Supracalycine nematophores stout, reaching to the level of the top of the hydrotheca; mesial 

 nematophore short, adnate to the hydrotheca for the greater part of its length, with the distal end 

 forming a short spur-like projection. 



Qonoxomc. A closed corbula with its distal end narrowed and projecting forward like a beak. 

 There are about ten pairs of leaves, each with a row of nematophores on its distal edge aud a long 

 spur-like projection at its base. There is a single hydrotheca between the corbula and the stem. 



Distribution. Key West, Florida, 3 to 4 fathoms; Albatrosx Station 2333, lat. N. 23 11', 

 long. W. 82 19', 10!) fathoms; off Habaiia, Cuba, loO to 250 fathoms, State University of Iowa 

 Expedition. 



