LACAZE-DUTHIERS ON CORAL. 303 



supposed to be ; but, without giving any positive opinion respecting 

 the function of this particular part of the organization, he acknow- 

 ledges that the food is often found below it, in the general cavity of 

 the body. 



The sarcosoma or bark of the coral is next described, and the 

 form, development, and distribution of the spicula minutely ex- 

 plained. This is followed by a detailed and interesting account of 

 the system of vessels by which the so-called "milk" of the coral is 

 circulated through the entire polyp-mass, or zoantliodeme, as the 

 author designates it. This milk escapes in some quantity when the 

 extremity of a living branch is broken or scratched. It is described 

 as consisting of a transparent fluid containing epithelial cells and 

 slightly-developed spicula with, at certain times, imperfect ova, and 

 spermatozoa. No mention is made of the numerous corpuscles 

 usually found in the circulating fluid of similar zoophytes, and especi- 

 ally abundant after digestion has taken place, giving to it the incipient 

 character of blood ; but it is subsequently spoken of as containing 

 '*the constituent elements of the polyp and the bark," so that the 

 nature of the fluid is obviously the same as in kindred species. No 

 independent aquiferous system was found to exist in Corallium ; and 

 the superficial pores formerly believed to be for the passage of water 

 are here shown to mark only the site of newly-budding polyps. 

 There is, in fact, nothing to show that the water obtains access to 

 tlie interior of the sarcosoma except through the mouths of the 

 polyps. In the chapter on the mode of increase by budding {blasto- 

 genhe) some interesting particulars are given of the production of 

 the polyps, and the manner in which injuries are repaired by a tem- 

 porary diversion of the blastogenetic energy. It was also observed 

 that the accidental contact of living branches soon resulted in a 

 complete connection between the two parts. This, we beheve, has 

 not been before described as taking place in Corallium or its allies, 

 although Dana has shown that such a union is of frequent occurrence 

 in Madrepora and in other forms among the true stony corals. 



In order to obtain a definite knowledge of the structure of the 

 veritable coral {polypier) thin longitudinal and transverse sections 

 of it, carefully polished, were found by the author to be essential ; 

 and these sections, when examined under the microscope, made 

 everything clear and intelligible. The coral is described as being 

 made up of successive layers of calcareous matter, and presenting, 

 under transverse section, a series of concentric circles, surrounding 



