April 11, 1902.] 



SCIENCE. 



577 



probably to be regarded as vestigial cells 

 which have been supplanted by other mes- 

 enchyme cells. 



A Case of Compensatory Regeneration in 

 Hydroides dianthus: C. Zeleny. (Read 

 by title only.) 



Primary Hexamerism in the Bugosa (Tet- 



racoralla): J. E. Duekden. (Read by 



title only.) 



Numerous serial sections of the rugose 

 coral, Lophophyllum proliferum (McChes- 

 ney), prepared for the author by the 

 United States National Museum, enable 

 him to confirm the observation of Pour- 

 tales in 1871 that six primary septa occur 

 at the tip of the corallum. Duncan and 

 Kunth have independently found the 

 Palaeozoic Heterophyllia, and Freeh the 

 Devonian Decapliylhim, likewise to be pri- 

 marily hexameral, while apparently no sec- 

 tions of any rugose types have been de- 

 scribed revealing only the four primary 

 septa which are usually assumed to be 

 characteristic of the Tetraeoralla. There 

 is good reason for concluding that the 

 Palaeozoic corals were primarily hexam- 

 eral, as is the case with modern corals and 

 actinians (Ceriantheffi excepted). 



The serial sections of Lophophyllum 

 beyond the tip permit of the order of 

 appearance of the later septa being estab- 

 lished. These are found to arise in bilat- 

 eral pairs within four of the primary in- 

 terseptal chambers in conformity with 

 Kunth 's law. Instituting a comparison of 

 this method of septal increase with what is 

 known of the mesenterial and septal suc- 

 cession in modern Zoantharia, it is shoMm 

 that the rugose corals are very closely 

 related to the living Zoanthid polyps. In 

 the latter new mesenteries appear at one 

 region within only two primary exoccelic 

 chambers, while in the Rugosa they must 

 have appeared in the same manner within 

 four primary chambers and rarely within 



six. The Zoanthids probably bore much 

 the same relationship to the corals of 



Paleeozoic times which the actinians of to- 

 day bear to recent corals. 



The Course of the Blood Plow in Lum- 

 hricus: Saeah Waugh Johnson. (Re- 

 ported by J. B. Johnston.) 

 The course of the blood flow in Lum- 

 hricus terrestris was studied by watching 

 the pulsations, cutting the vessels, holding 

 with forceps, and by various combined and 

 indirect experiments. The main result is 

 to show that the circulation in Lumhricus 

 is not fundamentally a segmental one, 

 upon which a partial systemic circulation 

 has been superimposed, but is wholly sys- 

 temic. The blood flows forward in the 

 dorsal vessel to the extreme anterior end 

 of the worm, downward in the hearts, and 

 in both directions from the hearts in the 

 ventral vessel. The flow is backward in 

 the subneural vessel and upward from the 

 subneural to the dorsal in the parietals. 

 From the ventral vessel the blood goes to 

 the intestine, body wail, and nephridia. 

 From these organs it is gathered up by the 

 dorso-intestinals, branches of the sub- 

 neural, and parietals, and emptied into the 

 dorsal. Thus the blood is carried back- 

 ward by the longitudinal trunks on the 

 ventral side of the body, upward through 

 the body wall, intestine, nephridia, etc., to 

 the dorsal, and forward in the dorsal to 

 the hearts. Since the floAv is upward in all 

 the circular vessels, no complete circuit 

 within a single segment is possible for any 

 part of the blood. In the anterior end of 

 the worm blood is carried forward by both 

 the dorsal and ventral vessels, and back- 

 ward by the subneural and lateral vessels. 

 The latter have connections in several seg- 

 ments with the subneural, anastomose 

 with the parietals of segments XII. and 

 XIII., receive blood from the body wall, 

 nephridia, and seminal vesicles, and empty 



