98 AMERICAN HYUKOIDS. 



AGLAOPHENIA PERPUSILLA Allman. 



(Plate XXI, figs. 4,5.) 

 Aglaophenia perpusilla ALLMAN, Mem. Mus. Comp. Zool., V, No. 2, ]>. IN. 



Tropliosomt. Hydrocaulus attaining the height of about } inch; stem simple, nonfaseicled; 

 plume alternate, each springing from the anterior aspect of an interuode in the axil of a strong 

 tooth-like process, which carries on its proximal side a fixed nematophore, just below which 

 another strong fixed nematophore also springs from the intcrnode. Hydrotheca' deep, slightly 

 widening upward; margin with about nine strong and deeply cut teeth, the anterior tooth con- 

 tinued into a narrow keel which runs down the front of the hydrotheca; intiathecal ridge distinct, 

 horizontal, situated at the junction of the lower and middle third of the hydrotheca. Supracaly- 

 cine nematophores strong, overtopping the hydrotheca; mesial uematophore scarcely reaching 

 the intrathecal ridge, aduate as far as its oblique terminal orifice. 



Gonosome. Not known. 



Dredged off the quicksands from a depth of 34 fathoms. 



I have not seen this species and have copied Professor Allmaii's description entire. The 

 distinguishing features are the narrow hydrothecal keel, and the supracalycine uematophores 

 which overtop the hydrotheca'. The processes of the hydrocladium are nearly half as long as the 

 height of the hydrotheca to the bases of the marginal teeth. 



Type. In the Museum of Comparative Zoology, Cambridge, Massachusetts. 



AGLAOPHENIA MAMMILLATA, new species. 

 (Plate XXI, figs. (i-lo. i 



Trophosome. Colony sparsely branching, attaining a height of 1.1 inches, growing in clusters 

 from a creeping rootstalk which is not regularly annulated; stem not fascicled, divided into 

 regular interuodes, each of which bears a hydrocladium from a process near its distal end; hydro- 

 cladia alternate, divided into regular interuodes, each of which has an internal ridge reaching 

 around its cavity behind the intrathecal ridge, and another below the supracalycine uematophores; 

 nodes very distinct. Hydrotheca- deep, closely approximated, with a narrow anterior keel reach- 

 ing to the margin, which is armed with nine sharply cut teeth; intrathecal ridge evident and 

 oblique, reaching clear around the hydrotheca' ; supracalycine nematophores rather small, not 

 overtopping the hydrotheca'; mesial nematophore stout, with its free distal portion divided from 

 the rest by a constriction or partial septum. There is an ordinary cauline nematophore at the 

 lower end of each internode of the stem, and a mammillate perforated process at the base of each 

 hydrocladium. 



Gonosome. Not known. 



Distribution. Albatross Station 2623, lat. N. 33 38', long. W. 77 36'; depth, 15 fathoms. 



The diagnostic marks of this species are its height, which is very much greater than in any 

 others of the minuta group, the narrow hydrothecal keel in connection with the absence of distinct 

 annulatious on the rootstalk, and the processes at the bases of the hydrocladia being smaller than 

 in the related species. 



Type slides. Gat. Nos. 18653, 18654, U.S.N.M.; Cat. No. 15361, Mus. State Univ. Iowa; also in 

 the collection of the author. 



AGLAOPHENIA MINIMA, new species. 

 (Plate XXI, tigs. 11-13.) 



Trophosome. Colony un branched, exceedingly delicate in texture, attaining a height of one- 

 fourth inch; stem not fascicled, slender and transparent, divided into regular internodes, each 

 with a bifurcated process bearing the hydrocladium, and another long, slender one some distance 

 below it on the proximal end of the internode; nodes distinct; hydrocladia slender, delicate, divided 

 into slender iuternodes, each of which has a septal ridge opposite the intrathecal ridge. Hydro- 

 theca. very thin and easily collapsed, deep, anterior profile straight and without a keel; aperture 

 oblique, surrounded by eight sharp teeth; intrathecal ridge evident, more nearly horizontal than 



