52 CLADOCAEPrs ye>;teicosus. 



Cladocai-pus ventricosus. 



PI XXXI. 



Trophosome. — Stem attaining a height of about an inch and a half, 

 not fascicled, simple : pinnae alternate, each spi-inging from a rather long, 

 lateral process of the stem, somewhat waved. Hjdrothecae distant ; front 

 wall with a depression just below the margin, then greatly inflated ; 

 margin with a long, strong tooth in front, and with shallow ci'enations 

 in the rest of its extent; intrathecal ridge strong, transverse, springing 

 from a projection of the posterior wall of the hydrotheca near its fun- 

 dus, and reaching a point about midway between this and the anterior 

 wall. Supracalycine nematophores scarcely overtopping the hydrotheca ; 

 mesial nematophore quite detached from the hydrotheca. 



Gonosome. — Phylactogonia springing from the proximal internodes of 

 a certain number of the pinnae, which are situated near the distal end 

 of the stem, twice bifurcating ; gonangia springing from the stem in 

 groups, each group close to the axil of a pinna, obovate, with the sum- 

 mit curved over the termino-lateral orifice. 



Dredged oft' Sand Key from a depth of 100 fathoms. 



This is a well-marked form ; its singular ventricose hydrotheca?, and 

 the complete removal of the mesial nematophore from the hydrotheca, at 

 once distinguish it. In Cludocarpus dolichoihecu the mesial nematophore, 

 while equally free from the hydrotheca, originates close to its base, but 

 in the present species its point of origin is removed much farther back, 

 and the entire nematophore is adherent to the front of the internode. 

 The septal ridges of the hydrothecal internodes are very distinct. 



Where the stem towards its proximal end ceases to carry pinnte, it is 

 provided with two or three very oblique joints, each of which carries a 

 fixed nematophore, and similar nematophores are continued down the 

 stem in a longitudinal series, at short and equal intervals (Fig. 5) ; here, 

 again, as in Cladocarpiis dolicJwtheca, strongly suggesting the disposition of 

 the denticles in one of the single-sided graptolites. Near the base of the 

 stem the nematophores may become biserial and opposite. Cauline nema- 

 tophores are also situated, one on the axil of each pinna and one on 

 the stem in the intervals between the pinnte. The sex of the gonan- 

 gia could not be determined. The phylactogonium has a single bifur- 

 cation close to its origin, and one of its branches again bifurcates. 



