422 Miscellaneous. 



Bafely speculate on the relationships of Echinoderms to Nemerteans 

 &c, we must get a clear understanding of the evolution of the class 

 itself. Towards this understanding no two investigators have con- 

 tributed more than Johannes Muller in his memoirs, and Ludwig in 

 his classical ' Beitrage.' But much remains yet to be done, and it 

 was with a view to add something to our knowledge of this group 

 that I began my work, at the suggestion of Dr. Brooks, at Beaufort, 

 early last June. These Notes are rather an earnest of what is to be 

 than a synopsis of what has been done. 



The Echinoderms of Beaufort represent all the orders except the 

 Crinoids, and with one or two exceptions are abundant, easily ob- 

 tained, and in their variety offer excellent material for comparative 

 work and for the solution of puzzling and important questions. 



The starfish are represented by Asterias Forbesii, Luidia cla- 

 thrata, Astropectenarticulatus, and an undetermined species, of which 

 I found only one specimen. This specimen was closely related to 

 Luidia and Astropecten, and may prove to be a cross between the 

 two — which surmise suggests some experiments in a field which cer- 

 tainly is promising. Of the Ophiurids great numbers of Ophiothrix 

 angulata are found in tbe cavities of the sponges so abundant in 

 certain parts of the harbour; some OpMophragma Wurdemanii, 

 Lyman, are found in the saud on Shark Shoals. Great numbers of 

 Ophiurn olivacea are found among the eel-grass in various parts of 

 the harbour, and one undetermined species was dredged in deep 

 water. The Echinoids are represented by thousands of the Cly- 

 peastroid, Mellita petapora, Liitk., commonly known as the sand- 

 dollar, great numbers of Sea- Urchins, Arbacia and Strongyloeen- 

 trotus, and by one Spatangoid, Moira alropos, which is common in 

 the sand on Shark Shoals. The Holothurians are represented by 

 Synapta and several undetermined species. 



When I arrived at Beaufort last June, the sand-dollar was spawn- 

 ing, and I accordingly began my work on it. The eggs, when laid, 

 are surrounded by a gelatinous membrane, in which are lodged 

 numbers of large purplish-red pigment-granules, which vary in size 

 and shape, and are always more or less angular. Fertilization takes 

 place through this membrane. In no case could I see anything 

 like a polar globule. The first two planes of segmentation (meri- 

 dional) and the third, which is equatorial, divide the egg into 

 eight blastomeres of equal size — occasionally the four at one pole 

 are a trifle larger than the four at the opposite pole. After eight 

 blastomeres are formed irregularities in segmentation begin, but as 

 I did not pay special attention to segmentation I shall not attempt a 

 description of the process. 



After the blastosphere is formed each cell acquires a cilium ; the 

 larva then begins to rotate within the membrane, and at length 

 wears through one portion of it and then escapes into the water. 

 It is generally stated that the blastosphere and gastrula of Echino- 

 derms are uniformly ciliated. This, I am prepared to say, is not 

 altogether true — at least it is not true for all the forms studied at 

 Beaufort. 



At the pole opposite to where the blastopore is formed is a small 

 circular area in which the cilia are longer, stronger, and less active 



