320 SUMMARY OF CURRENT RESEARCHES RELATING TO 



Biological Studies on Corymorpha.* — H. B. Torrey describee 



Co7\i/)>i<ir/i//tr [tiilinn both adult and young forms — and discusses its 

 activities in movement, feeding, and the like. 



It is unusually active for a hydroid. It is everywhere sensitive to 

 mechanical stimuli, irritant chemicals and abrupt changes in temperature, 

 nowhere to odorous substances. 



The prehensile mechanism is composed of proximal tentacles which 

 move toward the mouth in response to all effective stimuli ; distal 

 tentacles which move away from the mouth in their initial response to 

 stimuli ; and a proboscis, which may move toward the point stimulated. 

 These movements, as well as shortening and possibly lengthening the 

 stem, are performed by muscles. 



The stem of the adult responds to the stimulus of gravity by means 

 of a change in the turgidity of the vacuolated axial cells. The response 

 of these cells varies according as the stem is attached proximally or 

 distally, and according as it is heteromorphic or not. The polarity of 

 the stem is expressed not only by the regenerative development, but by 

 changes in the axial cells. 



Locomotion is accomplished by amoehoid cells located at the proximal 

 end in the adult, more generally distributed in the larva, and covering 

 the club-shaped ends of the filaments of the hold-fast. 



Cilia are present on the epithelial cells lining the hydranth cavity 

 and the peripheral canals. Supplemented by contractions and expan- 

 sions of the hydranth cavity, they provide for the circulatory currents 

 through the body. 



Eggs are laid both in summer and winter, usually during the 

 morning hours. They have adhesive coats. The planulae are never 

 ciliated, and their locomotion is limited to very slow creeping movements. 

 The larvae are geotropic. 



Gymnoblastic Hydroids of Western Mediterranean.! — S. Motz- 

 Kossowska gives an account of gymnoblastic hydroids collected near 

 Banyuls and neighbouring coast and Balearic Islands. Seven new 

 species and two new varieties are recorded. A marked resemblance to 

 the fauna of the bay of Naples was noted. The paper includes a 

 discussion of the phylogenetic position of the several members of the 

 group. The author agrees with Schneider in placing the Corynidae at 

 the base of the system, and from a typical Corynid with capitate 

 tentacles recognises a departure along three distinct lines, viz. (a) 

 diminution of the number of tentacles, e.g., Tlarella singnlaris ; (b) 

 diminution of number of tentacles and atrophy of the capitula of the 

 proximal whorl, e.g., Cladonema: Goryne pintheri and Stauridium 

 productum being intermediate ; (c) great development of proximal 

 circle of filiform tentacles as Tubularia with Pennaria intermediate. 

 It is possible that those Corynids with stinging buds on the external 

 face of the tentacles {Tiarella') may have given rise to forms with 

 ramified tentacles like Cladocoryne. 



Notes on Hydromedusaa from Naples.^ — Chas. W. Hargitt has 

 studied several species, some of which are believed to be new, others 



* Journ. Exper. Zool.. i. (1904) pp. 395-422. 



t Arch. Zool. Exp., iii. (1905) pp. 39-9S (1 pL). 



t MT. Zool. Stat. Neapel, xvi. (1904) pp. 553-85 (2 pis.). 



