ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 54T 



Tunicata. 



Arctic and Antarctic Appendicularise.* — H. Lohmanu describes 

 five species of Oikopleura and two species of Fritillaria from polar seas. 

 The only species distributed at both poles is Fritillaria borealis, but it 

 occurs in- several forms and is practically cosmopolitan. The polar 

 species of Oikopleura are characterised by a peculiar disposition of the 

 primordium of the " house," but the arctic and antarctic species are 

 quite distinct. In the antarctic species the gonads invest the gut 

 laterally ; in the arctic species they lie in the loop of the gut. According 

 to Lohmann the polar species of Appendiculariae are in no way old- 

 fashioned or primitive species. On the contrary, the polar species of 

 Oikopleura are probably the youngest and most highly developed species 

 of their genus. There is no warrant for supposing a monophyletic 

 origin for the polar Appendicularise. 



INVERTEBRATA. 



Mollusca. 

 a. Cephalopoda. 



Phosphorescent Organ in Cephalopods.t — "W. Th. Meyer has 

 examined this organ in Sepiola rondeletii ; he gives a description along 

 with comparative notes regarding Heteroteuthis dispar. The organ in 

 S. rondeletii is paired, lying right and left of the hind gut, is of the 

 form of an " ear-shell," and iridescent in the living animal. Three 

 portions are recognisable, one of which is glandular. An interesting 

 feature is the fact that this organ does not occur in all examples ; it is 

 absent in one half to three-fifths of them. It is not a case of sexual 

 dimorphism, for the organ may be present or absent in both sexes j 

 further, it may be absent in adults, and it has been found in immature 

 individuals. It is possible that two varieties of S. rondeletii exist, 

 whose only distinguishing feature is the presence or absence of this 

 organ. Steenstrup describes two varieties differing amongst other things 

 in the form of the ink-bag. It is a fact that this structure is modified 

 considerably by the presence of the " Leucht-organ." 



Sex Organs of Cephalopods.J — C. Chun gives an account of the 

 sex apparatus in the two deep-sea genera Galliteuthis and Histioteuthis. 

 W. Marchand describes the male organs of Ocythoe tubermlata, discussing 

 the peculiarities of these in the Octopods, while W. T. Meyer deals with 

 the same structures in Opisthoteuthis depressa. It would appear that 

 there are a number of points of difference in the male sex apparatus 

 between Octopods and Decapods. 



y. Gastropoda. 



Behaviour of Pond Snail.§ — H. E. Walter has made a special study 

 of the behaviour and reactions of Lymnmis elodes Say. It is negatively 



* Zool. Jahrb., Supp. viii., Festschr. f. Mobius, 1905, pp. 353-82 (2 pis.). 

 t Zool. Anzeig., xxx. (1906) pp. 388-92 (3 figs.). 

 X Op. cit., xxix. (1906) pp. 743-60. 



§ Brooklyn Inst. Arts and Sciences, Cold Spring Harbor Monographs, No. 6 

 (1906) pp. 1-33. 



