158 SUMMARY OF CURRENT RESEARCHES RELATING TO 



Species of Gadus.* — H. C. Williamson has studied the specific 

 characters of the three smallest species of Gadus, viz. G. li/scus, G. 

 minutus, and G. esmarJcii, and gives a carefully worked out comparison, 

 dealing with the dimensions, the number of fin-rays and vertebrae, the 

 skulls, the reproduction, etc. He makes it very clear that the sum or 

 resultant of the characters is the only sure basis for diagnosis. There is 

 hardly a single character that can be absolutely depended on. A key to 

 six species {G. callarias, G. virens, G. polhichius, and the three named 

 above) is given. 



Hermaphroditism in Cod.f — H. C. WiUiamson reports on two 

 cases of hermaphroditism in Gadus callarias. In one case the fully 

 developed female gonads bore a small testis at the anterior end of each 

 ovary ; in the other a single ovary on the right side was associated with 

 a full-sized testis on the left. In the first case the roe was nearly ripe, 

 the testis was considerably short of being ripe. It is conceivable that 

 after the eggs are discharged, the ovary may function as a vas deferens. 

 In a hermaphrodite ling, described by H. M. Kyle, the ovary seemed to 

 function as a vas deferens and the oviduct for the issue of both eggs 

 and sperms. 



Plankton Studies.:}: — Angelo Senna gives a preliminary account of 

 the plankton collections made by the ' Liguria ' in its circumnavigation 

 of the glolie (r.)0;^-5), under the command of His Highness the Duke 

 of the Abruzzi. 



Some Vertebrate Abnormalities.§ — W. M. Smallwood reports a 

 number of abnormalities. In a female cat a double condition of the 

 post-caval vein extended from the union of the common iliacs to the 

 kidneys. This might be due to a persistence of the posterior cardinals 

 in this region. Another case was the persistence of the foramen ovale 

 between the auricles of a pigeon. In Necturus, a broad, short branch 

 of the splenic vein passed directly to the body wall where a number of 

 short, finger-like branches extended in all directions for a short distance. 

 Two cases of double spleen in Necturus are noted. 



Reptilian Freaks from Indiana. || — W. S. Blatchley describes four 

 two-headed snakes, one two-headed turtle, and {pace the title) one five- 

 lesfsred frosr, and one two-tailed salamander. 



Abnormalities in Fishes.f — James Johnstone describes an example 

 of Rata clavata which exhibited an arrested development of the pectoral 

 fins so that the head remained free from them. An account is also 

 given of a flounder, Fleuronestes Jiesus, which was pigmented on both 

 sides. It was further abnormal in that the left eye is situated on the 

 (secondary) dorsal margin of the head, being easily visible from the 

 " blind " side. The coincidence of these two more or less larval con- 

 ditions in an adult is noteworthy. 



* Twenty-fourth Annual Report Fishery Board for Scotland, 1905 (1906) pp. 

 116-58 (3 pis.). + Tom. cit., pp. 290-2 (2 pis.). 



* Raccolte Planctoniche (R. 1st. Stud. Sup. Firenze) i. (1906) pp. 1-49 (1 pi. 

 and 1 map). § Anat. Anzeig., sxix. (1903) pp. 460-2 (4 figs.). 



II Proc. Acad. Nat. Sci. Philadelphia, 1906, pp. 419-22. 



•f Proc. and Trans. Liverpool Biol. Soc, xx. (1906) pp. 330-5 (2 figs.). 



