658 SUMMARY OF CURRENT RESEARCHES RELATING TO 



readily suggests itself that the establishment of some sort of physio- 

 logical discontinuity between these areas may be the key to the causal 

 problem. It seems to be clear from experiments, that an interruption 

 of the physical continuity of two portions of a polyp by means of a 

 cut parallel with the course which would be taken by a normal fission 

 plane, tends to interfere with the physiological interaction of the sepa- 

 rated regions and to initiate the process of fission. Finally, the authors 

 give interesting proof of the occurrence of heteromorphoses ; more 

 than 50 p.c. of the anemones operated upon gave positive results. 



Habits and Reactions of Sagartia davisi.* — H. B. Torrey de- 

 scribes this sea-anemone, the Pacific representative of Sagartia lucm of 

 the Atlantic coast, and discusses its habits. It occurs clustered on the 

 valves of Chione or any object which can give it a foothold out of the 

 sand. It can move freely by means of multicellular amoeboid processes 

 of the foot-disk, and may creep more than an inch in an hour. It has 

 a marked tendency to assume as erect a posture as its situation will 

 permit. Its locomotor geotropism is especially interesting from the fact 

 that the major axis of the animal is not parallel with the direction of 

 locomotion. It is not stimulated by light in any way. 



The entire surface, with the possible exception of a small zone 

 between mouth and tentacles, responds to mechanical stimulation, and 

 the tentacles show very definite adaptive reactions, which are described 

 at some length. The animal can discriminate between mechanical and 

 chemical stimuli, and can make certain " choices " in its quest for food. 

 Torrey shows how the movements of the tentacles, and the beating of 

 the cilia of the lips and oesophagus, are adapted to swallowing what is 

 useful and disgorging non-nutritious bodies. The phenomena of 

 swallowing and disgorgement are carefully analysed. 



Variation in Sagartia lucise.f — G. C. Davenport has studied the 

 question of the number of stripes on this sea-anemone. There is a 

 range from to 20, but this has been found to be due to the fact that 

 longitudinal fission takes place in this animal with unequal apportion- 

 ment of the stripes. The individuals are always tending by means of 

 regeneration in the direction of twelve stripes and forty-eight mesen- 

 teries, though division may occur before the state of twelve stripes is 

 attained. 



' Albatross ' Corals.} — Emil von Marenzeller reports on the Madre- 

 poraria and Hydrocorallinae of the 'Albatross' explorations in 1891, 

 conducted by Alexander Agassiz. Of the former, he discusses Bathy- 

 actis symmetrica, Cladocora arbuscula, Madrepora (AmphiheUa) oculata, 

 CaryophyUia diomedece sp. n., another species of Caryopliyllia, a species 

 of FJabellum, Desmophyflum crista galli, and a new genus or species of 

 Oculinidae. Of the Hydrocorallines, he discusses Errina macroyastra sp. n., 

 Stylaster divergens sp. n., Stenohelia profunda, and Cryptolielia pudica. 



* Biol. Bulletin, vi. (1904) pp. 203-16. 



t Mark Anniversary Vol., 1903, Art. vii., pp. 137-46 (1 pi.). 



J Bull. Mu?. Zool. Harvard, xlii. (1904) pp. 75-S7 (3 pis.). 



