324 CALIFORNIA ACADEMY OF SCIENCES. [Proc. 3D See. 



the new forms, the one possesses features so markedly 

 different from any known genus of the Pedicellinidse as to 

 warrant the formation of a new genus. The other is 

 placed, at least provisionally, in the genus Gonypodaria 

 Ehlers (1890). 



Myosoma, gen. nov. 



Diagnosis. — Zoarium with stolon composed partly of successive polypide- 

 bearing segments and partly of alternate non-polypide-bearing segments; 

 both stalk and calyx muscular, the muscle fibers continuous from one into 

 the other; lophophore oblique. 



Myosoma was obtained by Professor Ritter at Dillon's 

 Beach near Tomales Bay, California. It has since been 

 found at Fort Point and at San Pedro, California. As the 

 name implies, its distinguishing generic characteristic is the 

 possession of a muscular calyx, a feature not possessed by 

 any other Entoproct known. Aside from the sphincter mus- 

 cle, the Entoproct calyx is peculiarly destitute of muscular 

 development. Ehlers (1890) describes certain muscle fibers 

 in the calyx of Ascopodaria macropus which are connected 

 with the nephridia, and others which he calls the lateral 

 wall muscles. But in no case is there such a development 

 as is found in this form. 



Myosoma spinosa, sp. nov. 



Plate XVI, Figs. 1-12. 



Both stalk and calyx with surface diiferentiated into a spiny and a non- 

 spiny region, the latter corresponding to the side of the polypide in which 

 the musculature is more strongly developed. 



A. Strticture. 



I. The Stolon. — The colony of Myosoma spinosa forms 

 a closely matted growth by the interweaving and fusion 

 of its stolons. The stolon secretes a chitinous layer which 

 is thicker on the under surface, and which serves both to 

 attach itself to the substratum, and to unite adjacent stolons 

 together laterally, thus forming a sort of band. From such 

 a stolonic band, branches may extend laterally, both from 



