144 



appears to inhabit the shallow waters near Chelsea Beach in 

 great numbers. After the memorable storm of April last, multi- 

 tudes were found on the Beach, many of them living. They are 

 commonly two to four inches in length, with their worm-like 

 body much attenuated posteriorly. They vary from a bright 

 red to a pale flesh color. 



The surface has the appearance of being encrusted with grains 

 of sand, thus, undoubtedly, suggesting the specific name adopted 

 by Dr. Gould. This, under the microscope, is seen to consist of 

 innumerable calcareous plates. The plates are nearly circular, 

 pierced with nine to twelve holes arranged around a central 

 opening which is itself sometimes quadrifid. The calcareous 

 deposit is thus quite similar to that of Stereoderma, but less 

 abundant. 



Neither suckers or any other external organs of motion are 

 discernible. 



Tentacula twelve, short, slender, undivided in the greater part 

 of their length, digitate near the extremity, not retractable, as in 

 many species. 



The oral circle has its parts so united as to constitute appa- 

 rently one unbroken calcareous ring. This ring is simply crenu- 

 lated anteriorly. Posteriorly it is marked by five broad, bifid 

 projections, similar to those which present in the opposite direc- 

 tion in other genera. To these the very slender retractor mus- 

 cles are attached. 



The intestine, upon opening the body, seems without flexures. 

 It is fastened to the lateral walls not by the usual mesenteric 

 bridles, but by many muscular threads, like those commonly sur- 

 rounding the cloaca. When these are separated the intestine is 

 seen to be folded twice, but in a peculiar manner. The folds 

 extend no further back than to the point where the caudiform 

 part of the body commences. This point corresponds then to 

 the cloacal region in other genera, as it is here we have the 

 origin of the respiratory organs, and from this to the anus the 

 intestinal and respiratory tube lines closely the cavity of the 

 body. Entire length of intestine about twice that of the animal ; 

 without muscular stomach. 



Respiratory trees three, with short branches, reaching nearly 

 to the anterior extremity of the body. 



