SPONGES OF BEAUFORT (N. C.) HARBOR AND VICINITY. 169 
fibers connecting with the main fibers by several roots. They are commonly united by other dermal 
fibers that may be called interconnectives, but these are few in number and irregular in distribution. 
The result is that the dermal skeletal reticulum has, in general, large meshes that approach the squarish 
or rectarigular shape. Characteristic meshes measure 1.6 millimeters by 1.9 millimeters, 2.2 millimeters 
by 2.5 millimeters, 2.5 millimeters by 2.5 millimeters, 2 millimeters by 4 millimeters. The dermal 
connectives in some specimens are very different in appearance from the internal connectives, in that 
they are slenderer than the average internal connective and of very pale spongin well filled with min- 
eral particles. In other specimens they differ from the internal connectives only in containing more 
mineral particles, while in still other specimens the dermal connectives do not differ in appearance 
from the internal ones. The difference in appearance between dermal and internal connectives is 
thus inconstant. It is, perhaps, in part correlated with a difference in growth activity. 
In one specimen the dermal connectives depart, over much of the surface, from the type. Typical 
connectives are developed, but the surface as a whole offers the following deviations from the type: 
(a) Instead of a few interconnectives, a comparative abundance of fibers develop between and 
around the principal connectives, thus producing reticula which encroach upon the interconular areas. 
Such reticula may be very fine. 
(b) In this specimen as in some others a good many large sand grains are scattered through the 
ectosome and on the surface; but, whereas in the other specimens they have not been incorporated in 
the skeletal fibers, in this specimen a great many of the dermal connectives include large grains that 
measure up to 250 4 in diameter. The grains lie in a longitudinal series in the connective and are 
surrounded by a thin layer of spongin. They may form a continuous series or be separated by inter- 
vals in which the connective remains of the usual thickness, about 4oto 50u. Such fibers resemble those 
of the species grouped together by Lendenfeld under the subgenus Psammocinia (1889, p. 579)- 
(c) A further complication is present in that some of the dermal connectives that have incorporated 
large sand grains are fascicular. Such ‘‘fascicular”’ fibers consist of several simple connectives that lie 
close together and are interconnected. Sometimes all the longitudinal components of such a fiber 
apply themselves to the same sand grain. Fascicular connectives of this kind may be 350 u wide, the 
constituent being strands only 20 p thick. 
The peculiarities of the dermal skeleton in this specimen are probably no more than individual 
differences. The specimens form a series, at one end of which are those without large sand grains; in 
the middle, those with large sand grains in the ectosome but not in the skeletal fibers; at the opposite 
end, the specimen in which many dermal connectives have incorporated the sand grains in question. 
The internal connectives are composed of yellow spongin and in general are without, or have only 
scanty, mineral contents. Close to the surface they may exceptionally contain more, but even then 
the mineral contents can not be said to be abundant. They range in thickness from about 35 w to 175 yu. 
The connectives are characteristically simple, the meshwork correspondingly coarse. The skeletal 
meshes in the macerated skeleton, which with the most careful treatment shrinks in some degree, may 
reach 2 millimeters in diameter. Common sizes for the largest meshes are: Width 1.5 millimeters, with 
aradial diameter of 1.2 millimeters; width 1.2 millimeters, with a radial diameter of 1 millimeter; 
width 1.2 millimeters, with a radial diameter of 500 to 600 uw. In the case of such meshes neighboring 
connectives are not united together. But very commonly neighboring connectives are united together 
by a few other fibers—‘“interconnectives,’’ as they may be called. The size of the mesh is thus cor- 
tespondingly reduced, although characteristically it still remains large, typical diameters ranging from 
300 to 600 yu. 
The interconnectives often become so numerous and complex that they, together with the connec- 
tives, form reticula that extend between the main fibers, thus making an approach to the condition 
characteristic of Hircinia fetida (Schulze, 18796, Pl. III, fig. 3), although the reticula in question are 
coarser and more irregular than in the latter species. 
Position of H. ectofibrosa in the genus.—The Beaufort species is in that group of 
forms which center around the Mediterranean sponges described by F. E. Schulze as 
Hircinia variabilis, in which the main fibers are simple or only slightly fascicular and 
the connectives characteristically simple. Lendenfeld combines these forms into a 
subgenus, Euricinia. In his definition of this subgenus the following clause must now 
