420 PROCEEDINGS OF THE NATIONAL MUSEUM VOL. m 



mesenteries. At the base 96 mesenteries and about the same num- 

 ber of tentacles are present. The retractors of the perfect mesen- 

 teries are bandlike; the parietobasilar muscles strong, forming a 

 distinct shelf ; the basilar muscles well developed. I have examined 

 the nematocysts of the tentacles and marginal spherules in three 

 specimens, the nematocysts of the other parts of the body in two. 

 The nematocysts of the marginal spherules are partly 41-60 by 

 5.6-7 IX (atrichs), partly 41-56 by 2.8-3.5 /a (basitrichs) ; those of 

 the column 10-22.6 by 1.52-2.8/x (basitrichs, probably two kinds) ; 

 those of the tentacles 19.7-26.8 by 2.5-3 fj. (basitrichs) ; those of 

 the actinopharynx partly 21.8-31 by 3-3.5 ju, (basitrichs), partly 

 19.7-22.6 by 4.2-5.6 ix (microbasic p-mastigophors) ; those of the 

 filaments partly 32.4-42.3 by 5-5.6 /x, partly 11.3-17 by 1.5-2.5 fx 

 (both basitrichs) , partly 19.7-25.4 by 4.2-5.6 fx (microbasic p-mas- 

 tigophors). 



Measurements. — The largest specimen, pedal disc 4 by 2 cm., 

 height of column about 5 cm. 



Collecting records. — Puerto Escondido, March 26, 1940, one 

 specimen, the largest; Angeles Bay, April 1, 1940, two specimens; 

 San Carlos Bay, Sonora, Mexico, April 4, 1940, three specimens. 



Additional distribution records. — Panama; Rialejo; Pearl 

 Islands; El Salvador. 



BUiVODOSOMA CALIFORNICA, new species 



Figure 78, g 



The pedal disc is well developed but narrower than the oral 

 disc. The whole column is provided with closely set vesicles, as 

 in other species of the genus. The fosse is shallow, the sphincter 

 well developed and circumscribed, of almost palmate type, or with 

 a short, thin main lamella. In figure 78, g, I have illustrated the 

 sphincter of a specimen from Angeles Bay ; sections of specimens 

 from Point Lobos and Tiburon Island indicate similar sphincters. 

 The three specimens fromx Puerto Escondido and the one from 

 Tiburon Island have marginal spherules in the fosse; the other 

 specimens apparently do not, but if they are present they must 

 be very rare. 



The number of tentacles ranges between 120 and 146 in the four 

 larger specimens. The oral disc is wider than the pedal disc and in 

 the very contracted specimen from Point Lobos it is folded, mainly 

 because of the strong contraction of the body. The longitudinal 

 muscles of the tentacles are well developed and ectodermal. The 

 number of siphonoglyphs varies: the specimen from Tiburon 

 Island has three; two individuals from Angeles Bay and the 

 specimen from Port Lobos two, symmetrically set (those from 



