586 MATNARD M. METCALF, 



branchial chamber. These projections are surrounded at their basis 

 by irregularly shaped gill-clefts arranged in a spiral manner which, 

 by extending on to the projections, impart to these a peculiar cork- 

 screw like appearance." 



"The dorsal lamina is very thick and has a smooth edge." 



"The intestinal canal forms a long loop on the left side of the 

 animal; the oesophagus is long and narrow, stomach small and 

 elongated, the intestine spacious, and the anus attached and with a 

 sharp, smooth edge." 



"The genital organs are the same as those of Eugyra, only they 

 are developed on the left side lying within the loop of the in- 

 testine." 



"Habitat. Atlantic Ocean, Eastern coast of North - America ; 

 Cape Cod." 



BostrichobrancJius molguloldes n. sp. 



Body not attached, globular, 3 cm in diameter. 



Test thin and would be transparent, were it not for the cottony 

 fibres that project in abundance over the surface of the whole body, 

 except the siphons and a small area between and around them. Here 

 the outer surface of the test is smooth. 



The siphons, which are very near together in the center of the 

 upper surface, were contracted in all specimens studied, but from 

 their appearance one would judge that when fully expanded they 

 would be from */2 to 1 cm in length. The branchial aperture is six- 

 lobed, the atrial aperture four-lobed. 



The branchial sac is not folded, but the blood vessels running 

 out from the great median vessel in front of the visceral mass form 

 six prominent narrow ridges on each side. These blood vessels are 

 bound to the wall of the branchial sac by thin mesenteries in which 

 are no traces of stigmata. This is very different from the folding of 

 the whole wall of the branchial sac as seen in Molgula manhattensis. 

 Transverse vessels arranged in five quite regular lines connect these 

 vessels on each side. The internal bars which carry the great blood 

 vessels are not papillated. 



The stigmata are arranged in small spirals, the apices of the 

 spires being drawn out into the branchial sac, forming small papillae 

 (inverted funnels) over the whole inner surface of the pharynx, 

 between the bars. No stigmata are present except upon the papillae. 



The tentacles are compound and very much branched forming a 



