1913.] Clark, Echinoderms from Lower California. 223 



The largest in 110 mm. aeross, but only 92 mm. long, owing to the fact that 

 both posterior divisions of the test (between the median lunule and the 

 postero-lateral notches) were long ago lost (bitten off?) and although healed 

 are not at all regenerated. One specimen is 25 mm. across, and the lunule 

 and all the notches, except the mid-anterior, are distinct. The smallest 

 specimen is about 14 mm. across and only the lunule and posterior notches 

 are clearly seen. These small specimens are pale brown, almost fawn- 

 color, while the adults are deep purplish-brown, almost black. 



Cape St. Lucas, Lower California. 



Mulege Bay, east coast of Lower California. 



Tiburon Island, Gulf of California. 



Nineteen specimens. 



Encope micropora. 



L. Agassiz, 1841. Mon. Scut., p. 50. 



These specimens are all large, measuring 90-120 mm. across, the length 

 not quite equalling the width. The color varies from dull yellowish-brown 

 to almost black. One specimen is labelled "Tiburon Island" but as all 

 the others are from the west coast of Lower California, while the other 

 Encopes from Tiburon Island are grandis, it seems possible there may have 

 been a slip in the labelling. Yet in view of the wide range of micropora, 

 its occurrence in the Gulf of California is most probable; indeed, it has been 

 recorded from Guaymas, Mexico. 



Ballenas Bay, west coast of Lower California. 



South end of Magdalena Bay, west coast of Lower California. 



Tiburon Island, Gulf of California. 



Ten specimens. 



Urechinus loveni. 



Cystechinus loveni A. Agassiz, 1898. Bull. M. C Z., Vol. 32, p. 79. 

 Urechinus loveni Mortensen, 1907. "Ingolf " Ech., Pt. 2, p. 50. 



This rare and remarkable echinoid is represented by only one complete 

 specimen, although the fragments of a number of others show that it is 

 common in certain places such as Station 5684. The test is so thin and 

 fragile and the depth at which the animals live is so great, it must be rarely 

 indeed that unbroken specimens are brought to the surface. The larger 

 of the two measurable specimens before me is 70 mm. long, 63 mm. wide 

 and 43 mm. high. According to Agassiz's figure, his specimen, 88 mm. 



