A.GASS1ZLA EXCENTRICA. 7 1 



Agassizia excentrica A. A.o. 



Florida, Cuba, 1. ' ; -'i fathoms. 



For list of Stations, see Bull M C Z., V., No. 9, p 193, 1878 ; VIII., No. 2, p. 83, 1880. 



/'/. XX V. 



When alive the tesl is covered with spines of a delicate pinkish gray color, 

 darkest al the base. The ambulacral areas arc covered with slender, long- 

 stemmed, small-headed pedicellariae, articulated al the base, while in the 

 interambulacral Bystem the miliaries carry slender, straight, or slightly 

 curved club-shaped spines, scarcely stouter than the stem-; of the pedicel- 

 lariae. The fascioles are still more thickly crowded with similar minute 

 pedicellariae and club-shaped miliary spines, but somewhal shorter, and 

 closely dotted with large pigmenl spots. 



The actinostome of the genus is marked for the irregular arrangement of 

 the buccal plates. The anal plates are few in number, often less than eight, 

 comparatively large, and form in the young stages a regular anal pyramid, 

 as characteristic as thai figured by Gray, Lov6n, and myself in Palaeostoma. 



A few of the tentacles of the odd anterior ambulacrum, near the apical 

 system, are fimbriated like those surrounding the buccal system; those 

 immediately following towards the ambitus are simple, with a slight sucking 

 disk like the tentacles of the anterior row- of pores of the lateral petaloid 

 ambulacra. Within the petaloid area the tentacles of the posterior rows are 

 broader, compressed, irregularly lobed at the extremity; the tentacles beyond 

 become, as in the anterior rows, simple towards the ambitus, and remain 

 so till they join the large fimbriated tentacles surrounding the buccal 

 system. The presence of large fimbriated tentacles near the apical system 

 in the odd ambulacral petal shows thai Agassizia is itself an embryonic 

 genus, other features of the same character are the general globular form, 

 and the rudimentary structure of the lateral anterior ambulacra j the an- 

 terior rows of pores of the posterior lateral ambulacra appear only after 

 the posterior rows are well developed. 



In a specimen measuring ■"> mm. in length, the firs! ambulacra! tentacles to 

 appear arc those surrounding the actinostome, which were nine in number 

 and already fimbriated. In the denuded tesl of a specimen of about the 

 same size, no trace of the subdivision of the tesl into coronal plates could 

 be delected; it consisted entirely of a close network of fine granulation. 



