BRACHIOPOD COMMUNITIES 75 



which usually results in a 5 degree variation in surface temperature 

 within a very short time. A wind driven and tidal current runs over 

 this area during most of the year. A calm area is present to the south 

 of Long Point which is not rich in animal life. Chlorinity records at the 

 50 fathom depth indicate a rather regular average of near 18.8% 

 (Emery, 1954). 



Four species of brachiopods, about which some minor taxonomic 

 problems exist, have been taken in these collections off the shore of Cata- 

 lina. The most conspicuous form is the "California pink lamp shell," 

 Laqueus californianus (Koch, 1848). This species has been taken by 

 the hundreds in some dredge hauls over certain areas in past years, but 

 more recently such concentrations have not been discovered, only rather 

 small groups or clusters having been taken. This suggests that the popula- 

 tion may fluctuate in size considerably from year to year. 



Typically Laqueus occurs in grape-like clusters, several individuals 

 attaching to some solid object or to each other. One such cluster con- 

 tained 31 individuals attached to the shell of a larger and older Laqueus. 

 They have also been found attached to the living shells of other species 

 of brachiopods (Fig. 2), and in several instances to the living shell of 

 the "California frog shell," Bursa californica Hinds. These latter cases 

 result in transportation of Laqueus which is not possible for the typical 

 articulate brachiopod. In the Catalina area this species has been taken 

 from 30 fathoms to 120 fathoms. Beyond the 50 fathom region, it has 

 been noted that the typical large form and pink color give way to smaller 

 form and a color which fades to white. These latter characters approach 

 those of the questionable and more northern subspecies, vancouveriensis 

 Davidson, 1887. In other areas L. californianus has been taken in depths 

 of 861 fathoms (Dall, 1920). 



Laqueus californianus is a member of the family Terebratellidae and 

 is a relatively recent species known only since the Pliocene, about 7,000,- 

 000 years. The distribution of the living forms extends from British 

 Columbia south to Point Loma, California, with the greatest concentra- 

 tion from central to southern California. 



The next most abundant species in the Catalina area is Terebratalia 

 occidentalis (Dall, 1871). It usually occurs in smaller numbers, approxi- 

 mately 1 to 100 LaqueuSj and is typically found singly or in small clusters. 

 It has been taken in clusters with Laqueus (Fig. 2). In this area T. 

 occidentalis is extremely variable as to the form of the shell. These varia- 

 tions within one collection may range from a complexly ribbed form with 

 as many as 24 ridges resembling the Pliocene species T. arnoldi Hertlein 

 and Grant, 1944, to a very smooth shell indistinguishable from the sub- 



