HYDROZOA. 
Ccel 13 
Thecomedusce. The enigmatical “ hydroid zooids of sponges ” described 
by Eimer [Zool. Rec. ix. pp. 476 & 477] are satisfactorily explained 
through Schulze’s description of Spongicola Jistularis, g. & sp. n. (16), a 
commonsalist of various Mediterranean sponges {S2)ongelia, Myxilla^ 
Esp>eria^ Suherites, Renicra), nearly allied to (identical with P) Allman’s 
Stejdianoscyphus, but differing through the loss regular annulation of the 
perisarc, the presence of a hypostome, the absence of a circular canal, and 
the existence of four internal, longitudinal ribs (productions of the 
hyaline lamella, invested with endoderra) in place of the four vessels 
described in Stepkanocyphus. This Hydrozoon is also nearly related to 
the “ Scyphistoma ” of Discomedusm (on the true structure of which some 
remarks are adduced). With reference to histology, the demonstration of 
an external longitudinal layer of true muscular cells, and the apparent 
presence of a layer of circular muscles inside the “ hyaline lamella,” are 
especially noticeable. 
C YLICOZOA (Lucernariid j;) . 
Taschenberg (18) reduces the Clarkian genera and species to the pre- 
viously known 6 species and 2 genera : Depastrum cyathiforme (Sars), 
Lucernaria quadricornis (Mull,), campanulata, Lmk., auricula^ Fabr., 
octo-radiata, Lmk., and leuclcarti^ sp, n. (the species from Heligoland, 
described by Mettenheimer). The species are easily distinguished (1) 
by the insertion of the tentacles on the margin of the disk or on eight 
arms, (2) the single or quadruple cavity of the stem, (3) the presence or 
absence of four muscular strings in the stem, and (4) of large or small 
marginal corpuscles (modified tentacles), &c. The group is characterized 
thus: — “Oup-shapod Modusarians, fixed at the dorsal polo through a stom- 
liko foot, and wearing at the superior free margin the tentacles, which 
are commonly grouped together in clusters. The mouth-tube, which 
protrudes freely at the centre of the ventral surface, leads into the central 
gastral cavity, which, at the base of the cup, communicates with the four 
wide radial canals. Sexes distinct ; sexual products developing as eight 
plaited bands in the walls of four genital sacs, excavated into the ventral 
aspect of the cup.” Errors of previous investigators (Clark, Korotnelf *) 
are pointed out, but in several of these points, c. the abolition of 
the difference between the Clistocarpidm and EleutherocarpidcB of Clark, 
the author is himself afterwards corrected by Claus (5) ; the genital 
organs in reality belong to the radial canals. The anatomy and histo- 
logy of L. leuckarti is fully worked out. The gelatinous layer between 
endoderm and ectoderm is characterized as mesoderm ; in this layer the 
muscles are placed (eight internal, radiating ; eight external, marginal) ; 
the sexual products also penetrate into the mesoderm, but are formed 
from the ectoderm. The gastral tentacles are compared with those of 
certain jelly-fishes and with the mesenterial filaments of Actinic^] no sense 
* A paper (Russian) of this author is cited, “ Attempt at a comparative study 
of the Ccelenterata. I. Lucernaria, and its systematic position.” Moscow (1876). 
Izv. Linb. Est. Antr. Etno. xviii. Known to the Recorder from Taschenberg's atid 
Claus’s abstracts only. 
