February 17, 1005.] 



SCIENCE. 



269 



1875, the Chimaera in 1877, and the 

 Ceratodus in 1887. Contrary to supposed 

 conditions at the first date, the speaker now 

 believes that in teleosts the olfactory bulbs 

 are always solid, and that their hollowness 

 in ganoids is a diagnostic character. Some 

 progress has been made upon the peculiar 

 conditions presented in the chimaeroids, but 

 much remains to be done with specimens 

 specially prepared. Attention was again 

 called to the ventral extension of the cere- 

 bral hemispheres in the dipnoans, and to 

 their remote affinities with the ganoids. If 

 the account by T. J. Parker of Scymnus 

 (or Scymnorhinns) in 1882 is correct, that 

 shark presents a nearer approximation to 

 the ideal type of the vertebrate brain than 

 any other form, but more specimens should 

 be studied. There was submitted a 

 dichotomous arrangement of the vertebrates 

 above the lampreys, differing in some re- 

 spects from that published in the Proceed- 

 ings for 1887, and in the Amencun Nat- 

 uralist, Vol. 21, 913 and 1033. It is based 

 mainly upon encephalic and cardiac char- 

 acters. For the first time stress was laid 

 upon the absence from all the holocephala 

 of the rectal pouch which is a constant and 

 peculiar feature of all sharks and rays. 

 llie Feeding and Other Reactions of 



Actinian and Coral Polyps: J. E. 



DuERDEN, University of Michigan. 



The paper describes the reactions of 

 actinian and coral polyps to mechanical and 

 chemical stimuli, founded i;pon experi- 

 ments conducted in the Hawaiian Islands 

 during a recent visit of the writer under 

 the auspices of the Carnegie Institution. 

 Studies similar to those of Loeb, Parker, 

 Torrey and Nagel were carried out upon 

 two species of actinians (Cribrina), pre- 

 liminary to those upon the corals Fungia 

 and Favia. The principal results are a 

 demonstration of the important part played 

 by mucus in the feeding and other processes 

 of the two groups of polyps, the conditions 



governing the inhalent and exhalent cur- 

 rents of the stomoda?um, and the move- 

 ments of small and large particles over the 

 disc. They may be summarized as follows: 



1. Small, non-nutritive particles falling 

 on the disc and tentacles become embedded 

 in a superficial layer of mucus always pres- 

 ent. They may remain there for some time, 

 dependent upon the state of activity of 

 the polyp. In the end the mucus is broken 

 up into shreds or patches and, with the 

 embedded particles, is wafted away by ex- 

 halent currents from the stomoda'um. 



2. Nutritive substances lead to an open- 

 ing of the mouth, the establishment of an 

 inhalent stomoda^al current, and a more 

 rapid secretion of mucus, surrounded by 

 which the substances are indrawn into the 

 digestive cavity. An inhalent current be- 

 ing established, objects are indrawn inde- 

 pendently of their nutritive value. 



3. In actinians the transference of food 

 to the mouth is largely assisted by the move- 

 ments of the tentacles, disc, and upper 

 part of the column ; but in corals the 

 stomodfeal currents, assisted by the secre- 

 tion of mucus, are the principal agents. 

 A complex system of mucous streams is 

 beautifully shown in compound corals. 



4. The movement of heavier particles 

 over the disc is largely due to thigmotactic 

 or recovery reactions on the part of the 

 polyp. Attention is drawn to the impor- 

 tance of this in the conditions under which 

 many actinians and corals live. 



5. The correlation of the various reac- 

 tions with the anatomical structure of 

 polyps is considered, and comparison is 

 instituted between the reactions of polyps 

 as fixed radiate organisms with those of 

 free bilaterally symmetrical animals. 



C celosporidiuni blattella', sp. n., a Sporo- 

 zoan Parasite of Blattella germanica: 

 How'ARD Crawley, "VVyncote, Pa. 

 The parasite lives in the Malpighian 



tubules of the host. It originates as a 



