666 CHORDATA 



FAMILY 2. CYNTHIIDAE. 



Body always attached, spherical or elongate, with a tough leathery 

 tunic which is opaque, often brightly colored, and usually not covered 

 with sand; siphons short and usually four-lobed; inner tentacles either 

 simple or branched; branchial sac large, with 4 or more longitudinal 

 folds or bars on each side; intestine on the left side; distinct kidney 

 absent, its place taken by scattered renal cells; gonads hermaphroditic: 

 several hundred species. 



Key to the genera of Cynthiidae here described: 



a Body not stalked or with a short stalk. 

 &! Oral tentacles simple and filiform ....... . .................... 1. STYELA 



I, Oral tentacles branched ................................... 2. CYNTHIA 



c a Body with a long stalk .................................... 3. BOLTENIA 



1. STYELA Fleming. Body sessile; branchial sac with not more 

 than 4 ridges on each side; tentacles simple and filiform: cosmopolitan; 

 over 75 species. 



S. partita (Stimpson) (S. aggregata var. americana Metcalf) (Fig. 



1,009). Body somewhat flattened and attached by a broad base; surface 

 not sulcated, hard, wrinkled, dark brown in 

 color; siphons square, elevated, each aperture 

 marked by alternating triangles of white and 

 purple; length 25 mm.; breadth 12 mm.: Mas- 



Fig. 1,009 styela partita sachusetts Bay to North Carolina ; in shallow 

 water; common, occurring in groups. 



2. CYNTHIA Savigny. Body sometimes with a short stalk ; branchial 

 sac with 6 to 12 longitudinal ridges on each side; dorsal lamina a ser- 

 rate or fringed membrane; tentacles branched; gonad paired: 100 

 species. 



C. castaneiformis Drasche. Peduncle about as long as body but 

 variable in length; body more or less globose in form and hirsute; 

 orifices prominent; tentacles 50; branchial 

 ridges 8 on a side; length 35 mm.: Puget 

 Sound and southerly; common. 



C. carnea Verrill (Fig. 1,010). Body flat 



and disc-like, oval, and deep red in color, at- FI &- 1>01 ^ t ^f ia carnea 

 tached by a very broad base; siphons small; 



length 12 mm.: Martha's Vineyard to Labrador; in shallow water; often 

 very common. 



C. pyrifonnis (Rathke). Sea peach. Body globose or elliptical, 

 often attached by a narrow base; surface velvety and pink, red, or 

 yellowish in color; length 75 mm. or less; width 30 mm.; siphons cylin- 



