GONIMARETIA INTERRUPTA. 245 



length of the labrum increases with age; the drawing was made from the smallest 

 specimen; in the next larger specimen the labrum reaches well below the middle 

 of the second pair of ambulacral plates and its length is about 4 mm. with a 

 width at middle of less than 2; in the largest specimen, the labrum is nearly 

 5 mm. long but its width is still less than 2. The color of test and spines in all 

 the specimens is very pale brown or a brownish white. 



The covering of spines is largely rubbed off in the material at hand and 

 the remaining primaries are all broken. Apparently the spines, both in size 

 and arrangement, are much as in G. tylota. Pedicellariae are scarce on these 

 specimens. The triphyllous with valves nearly .10 mm. long and .06 mm. wide 

 seem to be a little more elongated than those of tylota. No globiferous or ophi- 

 cephalous pedicellariae were found and the tridentate are all of one kind; these 

 may perhaps be called rostrate, as they are not at all like the tridentate of 

 tylota, and no other rostrate were seen. The valves are .40-.65 mm. long; 

 their form is intermediate between the tridentate of Homolampas (see PI. 146, 

 fig. 2) and the rostrate of Brissus (see Mortensen, 1913. Mitt. Zool. Stat. Neapel, 

 21, pi. 4, fig. 22); the blade is .09 mm. wide at base and .13 mm. wide near 

 tip in the largest examples, while the base is about .25 mm. in height and in 

 width too. 



This species is certainly very near tylota but aside from the lack of primary 

 spines dorsally, the much larger petals will serve as a distinguishing feature. 

 The test of laevis is not so high posteriorly and the subanal plastron is not so 

 prominent; the sternum too is not quite so keeled and the conspicuous point 

 at its posterior end is lower. It is a matter of considerable interest to find this 

 nearest relative of a Kei Islands species, on the Californian coast, and the inter- 

 est is enhanced by the fact that Lovenia, an allied East Indian genus, also 

 has a well-marked representative in western American waters. 



Station 2911. South of San Clemente Island, California. BotL temp, 

 about 53°(?) 60 fms. R., s. 



Gonimaretia interrupta. 



Lonchophorus interruptus Studer, 1880. Monatsb. Berlin Akad. Wiss., p. 880. 



It is a great pity that our knowledge of this species is not more complete. 

 The unique holotype was taken in 30 fms. on the west coast of Australia, but 

 Studer gives no more exact locality. Mortensen has examined the specimen 



