ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 453 



head. During a part of their course the auditory caeca are enclosed in 

 hony grooves, and for the terminal portion of their extent occupy the 

 interior of bony culs-de-sac. In this respect they recall the condition 

 seen in the Clupeidae, as also in the fact that they originate from an 

 anterior tubular portion of the air-bladder. In a discussion on the 

 significance of the connection between auditory organs and air-bladder 

 in Teleosts, the author comes to the conclusion that, though there can 

 be no doubt that the connection has physiological importance, yet at 

 present the exact significance cannot be definitely determined. 



Copulatory Organ in Cottus gobio.* — Dr. Georg Snrbeck notes that 

 the fact that the male of this species has — at least during the breeding 

 season — a distinct penis has hitherto been apparently overlooked. The 

 structure is apparently produced by a papillary elevation of the skin, 

 and bears the urinogenital pore at the tip ; it reaches a length of about 

 3 mm. The presence of this structure would suggest that fertilisation 

 is internal. 



Urogenital Organs of Polyptems and Amia.f — Prof. H. F. E. 

 Jungersen notes, infer alia, that in Polyptems bichir the vasa deferentia 

 are essentially like those of Teleosts, but quite different from those in 

 Lepidosteus and Acipenser. In the two last the extra-testicular network 

 communicates directly with the malpighian corpuscles of the kidney ; 

 in Amia the chief connection is with the ureter ; in Polyptems the extra- 

 testicular network is separate even from the ureter, as in Teleosts. A 

 general description of the urogenital system is given. 



Tunicata. 



New Composite Clavelinid4 — Maurice Caullery points out that 

 among social Ascidians there is a tendency to become composite. He 

 illustrates this by the series (a) Clavelina lepadiformis, (b) Podoclavella, 

 (c) Stereoclavella, (d) Pycnoclavella. 



In the Paris Museum collection he has found two- forms — species of 

 what must be made a new genus (Synclavella) — in which the various 

 individuals are completely imbedded in a common tunic. Individually and 

 developmentally they are true Clavelinids, but their mode of cormo- 

 genesis shows that the distinction between social and composite has not 

 much meaning. 



Structure of Tail in Appendicularidae.§ — Prof. Oswald Seeliger has 

 studied this organ with special reference to the question of the existence 

 of segmentation. He finds in the first place that, in regard to the struc- 

 ture of muscles and nervous system, the species of Fritillaria, of Oiko- 

 pleura, and of the other known genera, show similar conditions. The 

 muscular system consists of a one-layered cell-plate, lying free in the 

 primary body-cavity (segmentation cavity), and composed of segments 

 which may (Fritillaria) consist of the ten muscle cells, each cell con- 

 stituting a segment, or {OUcopleurd) of ten rows of cells, each row 

 constituting a segment. There is no constant relation between the seg- 

 mentation of nerve cord and that of mu?cles, and though at times it may 



* Zo. 1. Anzeig.. xxiii. (1900) pp. 229-30. t Tom. cit., pp. 328-34. 



X Comptes Rendus, exxx. (1900) pp. 1418-20. 



§ Zeitschr. wiss. Z^ol., lxvii. (1900) pp. 361-400 (3 pis. and 1 fig:.). 



