INVERTEBRATA, CRYPTOGAMIA, MICROSCOPY, ETC. 573 



Jensen's Turbellarian Worms of Norway. — Marine zoologists 

 will be interested in the appearance of this valuable work on the 

 marine flat-worms of the Norwegian coast. A number of new forms 

 are described in considerable detail, with excellent figures, while the 

 descriptive portion is preceded by full anatomical details. The work 

 is done in the careful, conscientious manner characteristic of Scandi- 

 navian zoologists. The descriptions are both in Latin and Nor- 

 wegian, so that the work is accessible to students in general. 



Reproductive Organs of the Marine Ectoparasitic Trematoda.* — 

 It is impossible in an abstract to do full justice to M. Carl Vogt's 

 careful descriptions of the generative apparatus of several of these 

 forms, which he has lately been examining at Eoscoff. A point of 

 especial interest is the discovery of the characters of the orifice of the 

 common reservoir or ootyp (Van Beneden). This opening has a well- 

 marked contour, and is surrounded by short fibres, arranged radially, 

 at the edge of -which there were obscure indications of ciliary move- 

 ments ; but what was more remarkable was that, from time to time, 

 the orifice effected movements which could only be compared to those 

 of swallowing, and it is proposed therefore to call it the " swallowing 

 orifice " (Schluckoffnung) ; its function is evidently to aid the germs 

 in their passage through their duct. The writer says that he cannot 

 describe his extreme astonishment when he first saw this orifice in 

 action in Dactycotyle, where the yolk-spheres and ova were thrown 

 about, jiist as a juggler plays with his balls. 



As to the female organs in general, it may be observed that the 

 germ-gland is in all cases simple ; it may be spherical as in Udonella 

 and others, or it may be elongated ; the branched vitelline ducts do 

 not vary much in character, and generally open directly into the 

 ootyp ; this latter organ is formed at the point where the ovarian 

 germ, the masses of yolk, and the semen meet ; in some it is saccular, 

 and in others canalicular. The oviduct varies in length, and the uterus 

 in capacity, in some cases being so small as to be only able to contain 

 a single egg. The most important diff"erences are to be found in the 

 copulatory organs. In Polijstomum and Calicotyle the parts are most 

 highly diflerentiated, and there are two female copulatory orifices in 

 addition to the opening into the uterus by which the mature ova are 

 evacuated ; in Microcotijle, Udonella, and others, this uterine orifice 

 appears to serve also as the copulatory orifice ; in Biplectanum there 

 is a special coj)ulatory duct, which is completely separated from the 

 uterus and its orifice, and has a common aperture with the penial pouch. 



The male organs exhibit greater variety. Udonella has a single 

 rounded testis ; in Pliyllonella and E])ibdella two testes lie on either 

 side of the median line, while in Dactycotyle and Dijjlectanmn and 

 others there are a number of testicular tubes scattered in the paren- 

 chyma or collected together about the median line. As to the etferent 

 ducts, they have, in Phyllonella, Epibdella, Udonella, and Calicotyle, no 

 other connection with the female organs than what is afi"orded by the 

 possession of a common orifice. In Dactycotyle a canal passes from 



* ' Zeitschr. wi.ss. Zool.,' xxx. 8uppl. (1878) p. 306. 

 VOL. II. 2 Q 



