1909 ] Bitter: Halocynthia johnsoni n. sp. 67 



gling numbers excepting in San Diego and Wilmington bays. 

 At San Diego it occurs abundantly on the piles of the city 

 waterfront, but it also is a dweller on muddy bottoms at some 

 places in the middle and upper bay. Just what characterizes 

 the localities favored, I am unable to say. At San Pedro it 

 has been taken scarcely anywhere else than in those portions of 

 Wilmington lagoon, or bay where the water is so shallow as to 

 he accessible to a small launch at high tide only. Here it was 

 taken during the .summers of 19(11-02 in great numbers, mingled 

 with rock-oysters and pectins. A few small specimens were the 

 reward of careful search by myself on the defiant rocks of Point 

 Conception at Xew Year's time. 1908. At no other outside points 

 has the species been taken, though more extensive search would, 

 without doubt, increase the range and number of places inhabited 

 by it. 



2. Diagnosis of the Species. Halocynthia johnsoni n. sp. 



Superficial characters-.— Variable in form, this largely de- 

 pendent upon habitat ; generally elongate antero-posteriorly, 

 somewhat larger at the broadly attached posterior end; siphons 

 varying in length but always evident, never widely separated 

 at base: color generally dark brownish yellow, this usually ob- 

 scured by mud and other foreign substances, inner surface of 



orifices bright red: surfact re or less irregular and corrugated, 



but rarely or never presenting positive tubercles; size : length 

 of largest specimens 6 to S cm. including siphons, thickness nearly 

 always less, sometimes by one-half. (PI. 7.) 



Test: — Varying in thickness not infrequently reaching 4 to 

 5 mm., less frequently falling to 1 mm.: varying also in con- 

 sistency from distinctly hard and firm to something approaching 

 fleshiness; surface in general rather even, tubercles wanting, and 

 ridges or other inequalities sparse, wide, and low; not well sup- 

 plied with blood-vessels. 



Mantle: — Bright red. particularly anteriorly, not transpar- 

 ent, rather thick. Musculature moderately strong on the siphons 

 and anterior half of body; an external layer of fine, irregular, 

 generally transverse fibers, and an inner layer of much stronger 

 radial fibers grouped in distinct bundles (PI. 8. fig. 2, m. mus.). 



