INVEETEBRATA, CRYPTOGAMIA, MICROSCOPY, ETC. 723 



are formed in the tissues of the animal ; into these the ova fall, and 

 there undergo further development. 



Notes on the Turbellaria.* — Dr. Ludwig Graff commences some 

 observations on this subject, with a not unfounded complaint as to 

 the confusion which he iinds to obtain in the systematic zoology of 

 this group, of which he promises a revision ; he then gives some 

 account of the urticating organs of these animals, as to which there 

 are at i^resent but few authentic reports ; in a new Stenostomum, which 

 he found at Trieste, and which ho dedicates to that veteran zoologist, 

 Siebold, he found urticating capsules, which were of interest as being 

 developed in just the same way as the rod-shaped bodies found in the 

 cells of the parenchyma, and so affording support to the doctrine 

 that the rods and the urticating capsules of the Turbellaria are homo- 

 logous structures ; in another new form — Stijlochus tardus — which was 

 also found at Trieste, the rod-shaped bodies were completely absent, 

 and the urticating capsules were in consequence very richly developed. 



Drawing attention to the fact that Graff has observed chitinous 

 structures, in the form of spines, in the integument of the Turbellaria, 

 we have to note that there are interspaces between the longitudinal 

 bands of the dermo-muscular tube, which have hitherto been regarded 

 as being in all cases continuous, and that the observations now under 

 notice confirm the view of the Russian naturalist, Uljanin, that some 

 forms among the Turbellaria have no ccelom ; in such forms the 

 nutriment jjasses by a narrow cleft into a soft medullary substance, 

 rich in vacuoles and fat-drops, which is very similar to what is seen 

 in the Infusoria, with which they seem, pro tanto, to have closer rela- 

 tions than is now ordinarily supj)oscd. In the great majority of 

 forms, however, there are distinct walls to the enteric tract, and the 

 coelom is then filled with a lacunar connective substance, the parts of 

 which may be thick and inclined to form broad plates, or thin and 

 feebly developed ; the contained fat-di-ops usually include a coloured 

 watery fluid, which has some influence on the external coloration of 

 the animal in those cases in which there are no other pigments pre- 

 sent ; as a rule, however, there are such, which are found imbedded in 

 the connective substance, while the epithelium itself is always colour- 

 less. The observation of Oersted, that the spermatozoa vary greatly 

 in character, is shown to be true of the rhabdocoelous, but not of the 

 dendrocoelous forms. Grafl"s further investigations will be awaited 

 with interest. 



Studies on the Nemertinea.t— Herr V. Kennel, in an elaborate 

 l)aper, deals with two very interesting forms, Malacohdella and 

 Geonemertes. Of these two, the former has long been regarded as a 

 Leech, but Semper and Hoffmann have shown that it rather belongs 

 to the Nemertinea than to the Hirudinea. The specimens examined 

 by Von Kennel were found in Cyprina islandica, and he notes that 

 they were never found in Mya arenaria ; the former molluscs, at the 

 station at which he observed — Kiel — were taken from a region which 



* ' Zeitsclir. wiss. Zool.,' xxx. (Suppl.). 



t ' Arbeit. Zool. Zoot. lust. Wiirzburg,' iv. (1878) p. 305 



