1917] Bitter-Forsijtli: Aacidians of Southern California 469 



Breeding season. — June aud July. Colonies collected in these 

 months had large eggs in the atrium while in colonies taken in January 

 the ovarian eggs were still small. 



Habitat and distribution. — In the littoral zone, usually on the 

 imderside of rocks. According to our present information extending 

 from San Diego to Dillon's Beach near the mouth of Tomales Bay. 

 The species has been taken on the rocks north of the Scripps Institu- 

 tion, La JoUa, though not in abundance. 



Type locality. — La Jolla. California. 



Eudistoma diaphanes, n. sp. 



Superficial characteristic.'^ of the colony. — Plat and encrusting, 

 soft, usually even surfaced and regular in outline. Rarely exceeding 

 10 cm. in greatest expanse, usually much smaller ; seldom if ever more 

 than 1 cm., frequently only a few millimeters thick. Color varying 

 from white to pale vermillion ; test transparent, containing a great 

 quantity of cellular material but no bladder cells or spicules; almost 

 entirely free from sand. 



Zooids. — Uniformly distributed; not disposed in systems; incon- 

 spicuous by reason of small size and meagerness of pigment ; placed 

 at various angles to .surface of colony. Length about 3 mm. ; less in 

 preserved condition. A distinct capsule of test enveloping each zooid. 

 Mantle musculature similar to that of Eudistoma p.sam.mion. Ecto- 

 dermal processes present but not as long and numerous as in E. 

 psammion. 



Branchial system. — Siphons relatively shorter than those of E. 

 psammion, the two of about equal length; both opening on surface. 

 As far as could be made out, branchial sac very similar to that of 

 E. psammion. Branchial tentacles about twenty in number, of two 

 sizes, not all in same circle but scattered somewhat over surface of 

 siphon. 



Digestive system. — Similar to that of psammion but violent con- 

 traction often obscures similarity. 



Feproductive system. — Similar to that of psammion. Specimens 

 from La Jolla collcM'ted in July had large eggs in atrial cavity. 



Habilat and di.'itribution. — On under side of rocks in littoral zone 

 from San Diego to San Francisco, according to our present knowledge. 



Type locality. — La Jolla, California. 



These two species of Eudistoma are quite similar as far as the 

 zooids are concerned ; but the striking differences in the colonies, and 

 the fact that E. rliaphanes does not have systems, and hence its two 

 siphons are of about equal length is our basis for recognizing two 

 species. 



The senior author has more or less carefullj^ examined specimens 

 presumably of Eudistoma diaphanes from many points on the Cali- 

 fornia coast between Cape Mendocino and San Diego. Unquestionably 

 much variation occurs within the range, particularly in the size and 

 color of the colonies, and it is by no means impossible that more 



