ENCOPE GRANDIS. 75 



Accompanying this change in the ambulacra, the genital pores of interambulacra 

 five and one have shifted their position and lie side by side, 2 mm. apart and 3 

 mm. from the madreporite in the region which is normally occupied by the petal. 

 The explanation of the whole appearance is, no doubt, that for some unknown 

 reason, ambulacrum I ceased to grow when the petal was 20 mm. long and the 

 region which it should have filled has been built up by the adjoining interambul- 

 acra, the unusual growth of which has caused the displacement of the genital 

 pores. It is important to note that ocular I is in position, fused to the madre- 

 porite as usual. This case falls into group 15 of Jackson's twenty combinations 

 of character in variations from pentamerous symmetry, and agrees almost 

 exactly with some of the cases found in regular Echini, which he studied (Jack- 

 son, 1912, Mem. Boston Soc. Nat. Hist., 7, p. 43). 



Encope michelini. 



Agassiz, 1841. Mon. Scut., p. 58. 



The pedicellariae of this species agree with those of emarginata. Its geo- 

 graphical range is much more limited, for it seems to be confined to the shores of 

 the Gulf of Mexico from Cape Florida and the Florida Keys around to Yucatan. 



Encope californica. 



Verrill, 1871. Trans. Conn. Acad., 1, p. 586. 



The bidentate pedicellariae of this species are like those of grandis, the tip 

 of the blade of each valve forming a long terminal tooth. Like grandis too in 

 its distribution, californica seems to be confined to the Gulf of California. The 

 Albatross collection contains two specimens, one a long-dead worm-tube 

 covered test, from 



Station 2828. Gulf of California, 24° 11' 30" N., 109° 55' W. lOfms. Sh. 



Encope grandis. 



Agassiz, 1841. Mon. Scut., p. 57. 



Plate 125, fig. &$. 



The bidentate pedicellariae have valves terminating in a conspicuous tooth 

 (PL 125, fig. 24), the margins being somewhat serrate. No other species of the 

 genus is as easily recognized as this and no other shows so little variability. It 

 seems to be also the least common member of the genus and appears to be con- 

 fined to the Gulf of California. 



