ZOOLOGY AND BOTANY, MICROSCOPY, ETC. . 299 



•energy is transformed into chemical energy in the granules by the pig- 

 ment. Not only so, but the formation of the eye is " a chemical phe- 

 nomenon," in which pigmentary and hyaline modifications of tissue occur. 

 In Vertebrates, it is noted, the eye is considered as a metamorphosed 

 branchial cleft. We have not been able to follow the argument. 



INVERTEBRATA. 



Mollusca. 

 o. Cephalopoda. 



Dichotomy of Arms in Cuttlefish.* — C. Parona describes a case in 

 •Octopus vulgaris. The divided arm was small and doubtless in process 

 of regeneration. In another case observed in Eledone aldrovandi, the 

 dichotomy was not obvious as such, but an extra arm arose between the 

 second and third on the right side, closely apposed to the third. Fisher- 

 men report the not infrequent occurrence of specimens of Eledone with 

 nine arms. 



Synopsis of (Egopsid Cephalopods.f — Dr. G. Pfeffer has made a 

 valuable synopsis of all the known cegopsid cephalopods, with the usual 

 diagnoses and identification tables. It has especial reference to the 

 cephalopods of the German Plankton Expedition — to be treated of in a 

 special report. 



3. Scaphopoda. 



" Pseudogamy " in Dentalium Entalis.J — Dr. V. Ariola has followed 

 Loeb's methods in treating the ova of Dentalium entalis with various 

 solutions, magnesium chloride, sodium chloride, Ac. in sea-watef and in 

 distilled water. In no case did the eggs exhibit osmotic pseudogamy, as 

 the author calls it. There was no beginning of segmentation. But a 

 comparison of the eggs in the artificial solutions with those in normal 

 •sea-water showed that the ions had a deleterious effect. 



y. Gasteropoda. 



Reactions of Limax maximus.§ — P. Frandsen has studied the loco- 

 motor responses of this slug to three kinds of stimuli, — those of touch, 

 gravity, and light. (I.) In ordinary circumstances the animal is nega- 

 tively thigmotactic, — moving away from the agent that comes in contact 

 with it. 



(II.) On an inclined glass plate, all slugs give a geotactic response, 

 some positively, others negatively ; a few are somewhat indifferent. 

 'There is little variation on different days or at different times on the 

 same day. The occasional vagaries in the responses of individual 

 animals are to some extent due to thigmotactic and phototactic in- 

 fluences. 



The different geotactic response, on a glass plate, of different in- 

 dividuals is due mainly to two factors : (a) the quantity and quality of 



* Boll. Mus. Zool. Univ. Genova, No. 96 (1900) pp. 1-7 (1 pi.). See Zool. Cen- 

 tralbl., ix. (1902) pp. 184-5. 



t MT. Nat. Hist. Museum Hamburg, xvii. (1900) pp. 147-98. See Zool. Cen- 

 tralbl., ix. (1902) p. 185. 



% MT. Zool. Stat. Neapel, xv. (1901) pp. 408-12. 



§ Proc. Amer. Acad. Sci., xxxvii. (1901) pp. 185-227 (22 figs.). 



