174 SOULE 



Phylum ENTOPROCTA Nitsche, 1869 



Family Pedicellinidae Johnston, 1847 



Colonial entoprocts, the zoids arising from a creeping segmented 

 stolon. For an excellent key to the genera of the Pedicellinidae see Os- 

 burn, 1953, page 761. 



Genus Myosoma Robertson, 1900 



"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." Robertson, 1900, page 324. 



The genus Myosoma was erected by Miss Robertson in 1900 on the 

 basis of material collected at Dillon Beach, California, the type locality. 

 In addition to the specimens from the type locality, Miss Robertson 

 reported the presence of the genus in collections from San Pedro, Cali- 

 fornia, and Fort Point, California. There is no further mention of the 

 genus in the literature for fifty-three years, until Myosoma spinosa 

 Robertson 1900 was recorded by Osburn, who found it in collections 

 taken at Dillon Beach, California, Newport Bay, California, and La 

 Jolla, California. 



From a re-examination of specimens of Myosoma spinosa Robertson 

 from Dillon Beach, California, and after study of the species described 

 below, the greater part of Miss Robertson's observations were confirmed. 

 However, with reference to the musculature of the pedicel (stalk, Rob- 

 ertson), it was found that while some muscle fibers are placed longi- 

 tudinally and others diagonally, in neither Myosoma spinosa nor in the 

 new species described below was the heavy "ventral muscle" band de- 

 scribed by Miss Robertson in evidence. 



Myosoma spinosa Robertson, 1900, the sole species known for almost 

 fifty-five years, is the genotype. 



Myosoma hancocki Soule, new species 



Diagnosis: With the characters of the genus. Zoarium forming dense 

 tangled masses upon the substratum. Stolon creeping, composed of both 

 polypide-bearing and sterile segments. Polypide consisting of a raised 

 pedicel, bearing at its apex a calyx. Pedicel with musculature arranged 

 both longitudinally and diagonally. Pedicel devoid of spines. Calyx with 



