AMERICAN HYDROIDS. 123 



(v. Frauenfeld); Mediterranean (Kattegat); Jamaica (specimens from Yale Museum); Panama 

 (specimens from Yale Museum); Bahia, Brazil (Rathbuu). 



Specimens from Panama and Babia are not constant in having all the branches directed 

 forward, as described by Bale. They also differ from Australian specimens in having shorter 

 mesial neuiatophores. 



LYTOCARPUS RAMOSUS (Fewkes). 

 (Plate XXXI, figs. 8-13.) 



Pleurocarpa ramosa FEWKES, Bull. Mus. Comp. Zool., 1881, VIII, No. 7, p. 136. 



Trophosome. 1 Colony branching in a subpiuuate manner and attaining a height of about 8 

 inches; stem fascicled almost to the tips of the branches, the anterior tube bearing the hydro- 

 cladia; nodes obscure; hydrocladia alternate, rather closely approximated, divided into regular 

 internodes, each of which has a very strong horizontal septal ridge behind the intrathecal ridge. 

 Hydrotheca^ closely approximated, rather deep, obcouic, aperture nearly horizontal; margin 

 armed with about eight large, broadly rounded teeth; iutrathecal ridge strong, oblique, reaching 

 forward toward the mesial nematophore; mesial uematophore considerably overtopping the 

 hydrotheca near the distal end of the hydrocladiniu, and scarcely rising above the hydrotheca on 

 the proximal portion of the hydrocladium; the anterior profile of the mesial nematophore is sinu- 

 ous, not strongly convex; supracalycine neuiatophores tubular, very long on distal part of 

 hydrocladia, and much shorter, scarcely overtopping the hydrotheca', on the proximal portion; 

 cauliue uematophores small for this group, with their free edges trilobate, one on either side of 

 the base of each hydrocladium. There is a rounded perforated process at the base of the 

 hydrocladium. 



Gonosome. A pseudo-corbula formed on the proximal portion of a branch which bears regular 

 hydrocladia on its distal portion, and also occasionally between the pseudo-corbula and the stem. 

 The ribs of the pseudo-corbula bear each a single hydrotheca near its base, and a number of 

 tubular nematophores in sets of three. The ribs are distinctly jointed, one joint bearing two 

 opposite uematophores and the next bearing a median uematophore in regular alternation. The 

 stem of this modified branch bears nematophores, but no hydrotheca'. The gonaugia are not 

 present, but are evidently borne on the ribs, as in L. clarkei. 



Distribution. Blul;e Station 231, off St. Vincent, 95 fathoms. 



It will be seen that this description differs from that of Doctor Fewkes in several particulars, 

 notably in describing the stem as fascicled, the psemlo-corbula ribs as having nematophores on 

 three sides only, and the corbula stem as not bearing hydrotheca^. A careful examination shows 

 that these hydrotheca' are actually borne on the so-called ribs near their bases, although this is 

 difficult to see without dissection. The species is very near Lytocarpits clarkei, but differs 

 decidedly in the anterior profile of the mesial uematophore, and especially in having much smaller 

 cauline nematophores than that species. 



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



LYTOCARPUS GRANDIS (Clarke). 

 (Plate XXXII, tigs. 1-1.) 



Xi-maloiihorus granHis CLAKKE, Bull. Mus. Comp. Zool., 1879, V, No. 10, p. 248, pi. v. 



Trophosome. Colony branching, branches generally alternate, flabellate, attaining a height 

 of 12 inches; stem and branches fascicled, except on their extreme distal portions, the anterior 

 tube giving off the hydrocladia; hydrocladia alternate, divided into regular internodes, each of 

 which has a very strong horizontal internal septum opposite the intrathecal ridge. Hydrotheca 1 

 rather closely approximated, robust, slightly constricted above, being ovate in outline; orifice 

 oblique; margin with about five rounded teeth, which have a tendency to curve inward; intrathecal 

 ridge very evident, horizontal and straight, extending clear round the hydrotheca, dividing the 

 lower one- fourth from the upper three-fourths; supracalycine nematophores large, tubular, extend- 

 ing far above the hydrotheca; mesial nematophore adnate throughout, extending decidedly above 



1 Description of Doctor Fewkes's type specimen from the Museum of Comparative Zoology. 



