ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 
181 
They claim as the result of their observations to have shown with 
certainty that there exist FilariaB which are propagated normally by the 
intervention of blood-sucking parasites, and they call attention to the 
resemblance of the larvae described by them to the Filaria found by 
Manson in Culex. 
Helminthological Notes.^ — Prof. M. Stossich catalogues and makes 
notes on fifteen parasitic worms from Croatian animals. The list 
includes Distomum croaticum Stossich, Cosmocephalus pa^illosus Molin, 
and EcMnorhynchus glohocaudatus Zeder. 
y. PlatyRelminthes. 
Anatomy of Derostoma unipunctatum.| — Herr K. Lippitsch has 
had an opportunity of investigating the anatomy of this Turbellarian. 
The cells on the surface of the integument are connected by a cementing 
substance, are more or less polygonal in form, ahd have their side-walls 
distinctly ribbed ; these cells vary considerably in size and form. No 
special deposits were seen in the epithelium, save some rods which lay 
at the anterior end of the body. The dermomuscular tube is well 
developed and consists of outer circular, internal longitudinal, and other 
fibres, which lie between and cross the outer and inner layers. Tbe 
structure of the connective tissue of the body-parenchyma is very similar 
to that of Graffilla, 
The oesophageal pouch, which lies between the mouth and pharynx, 
is not muscular ; the axis of the pharynx lies at an angle of 120° to the 
long axis of the body; its muscular fibres have no nuclei, and are 
smooth ; the author describes their arrangement in detail. The pharyn- 
geal glands have efferent ducts, which all open at the anterior end of 
the pharynx below the sphincter and on a kind of papilla ; the orifices 
of all the ducts form a circle. The glands themselves are of some size, 
and of an elongate pyriform shape; the protoplasm of their cells is 
either plexiform or granular, but it cannot as yet be decided whether 
these represent two kinds of gland or the same gland in two different 
stages of its activity. The pharynx is moved by two protractors and 
two retractors, the former of which are much more fully developed than 
the latter. An oesophagus, such as has been described by various authors 
in different freshwater and marine Vorticidae, could not be made out. In 
many cases the enteric cells were so filled with crystalloids, and often 
also with quite homogeneous discs, of elliptical or circular contour and 
with brown concretions, that the structure of the cells could not be 
distinctly made out. In a number of important points the gonads and 
their appendages appear to present essentially the same characters as in 
allied forms already described. 
The nervous system is well developed, and consists of two ganglia, 
connected with one another by a strong commissure ; the largest of the 
nerves appears to be the optic ; the dorsal and ventral nerves described 
by Bohmig have been made out, but the former presented some diffi- 
culties ; the generative nerve does not appear to be present. The author 
Glasnik hrv. nar. druztva, God. iv. (Soc. hist.-nat. Croatica), pp. 8 (1889) 
(2 pis.). 
t Zeitschr. f. Wiss. Zool., xlix. (1889) pp. 147-67 (2 pis.). 
